diff -r 000000000000 -r 6474c204b198 gfx/gl/GLContext.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/gl/GLContext.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,2038 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=4 et sw=4 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "GLContext.h"
+#include "GLBlitHelper.h"
+#include "GLBlitTextureImageHelper.h"
+#include "GLReadTexImageHelper.h"
+
+#include "gfxCrashReporterUtils.h"
+#include "gfxUtils.h"
+#include "GLContextProvider.h"
+#include "GLTextureImage.h"
+#include "nsPrintfCString.h"
+#include "nsThreadUtils.h"
+#include "prenv.h"
+#include "prlink.h"
+#include "ScopedGLHelpers.h"
+#include "SharedSurfaceGL.h"
+#include "SurfaceStream.h"
+#include "GfxTexturesReporter.h"
+#include "TextureGarbageBin.h"
+#include "gfx2DGlue.h"
+#include "gfxPrefs.h"
+
+#include "OGLShaderProgram.h" // for ShaderProgramType
+
+#include "mozilla/DebugOnly.h"
+
+#ifdef XP_MACOSX
+#include <CoreServices/CoreServices.h>
+#include "gfxColor.h"
+#endif
+
+#if defined(MOZ_WIDGET_COCOA)
+#include "nsCocoaFeatures.h"
+#endif
+
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+
+namespace mozilla {
+namespace gl {
+
+#ifdef DEBUG
+unsigned GLContext::sCurrentGLContextTLS = -1;
+#endif
+
+uint32_t GLContext::sDebugMode = 0;
+
+
+#define MAX_SYMBOL_LENGTH 128
+#define MAX_SYMBOL_NAMES 5
+
+// should match the order of GLExtensions, and be null-terminated.
+static const char *sExtensionNames[] = {
+    "GL_EXT_framebuffer_object",
+    "GL_ARB_framebuffer_object",
+    "GL_ARB_texture_rectangle",
+    "GL_EXT_bgra",
+    "GL_EXT_texture_format_BGRA8888",
+    "GL_OES_depth24",
+    "GL_OES_depth32",
+    "GL_OES_stencil8",
+    "GL_OES_texture_npot",
+    "GL_ARB_depth_texture",
+    "GL_OES_depth_texture",
+    "GL_OES_packed_depth_stencil",
+    "GL_IMG_read_format",
+    "GL_EXT_read_format_bgra",
+    "GL_APPLE_client_storage",
+    "GL_APPLE_texture_range",
+    "GL_ARB_texture_non_power_of_two",
+    "GL_ARB_pixel_buffer_object",
+    "GL_ARB_ES2_compatibility",
+    "GL_ARB_ES3_compatibility",
+    "GL_OES_texture_float",
+    "GL_OES_texture_float_linear",
+    "GL_ARB_texture_float",
+    "GL_OES_texture_half_float",
+    "GL_OES_texture_half_float_linear",
+    "GL_NV_half_float",
+    "GL_EXT_color_buffer_float",
+    "GL_EXT_color_buffer_half_float",
+    "GL_ARB_color_buffer_float",
+    "GL_EXT_unpack_subimage",
+    "GL_OES_standard_derivatives",
+    "GL_EXT_texture_filter_anisotropic",
+    "GL_EXT_texture_compression_s3tc",
+    "GL_EXT_texture_compression_dxt1",
+    "GL_ANGLE_texture_compression_dxt3",
+    "GL_ANGLE_texture_compression_dxt5",
+    "GL_AMD_compressed_ATC_texture",
+    "GL_IMG_texture_compression_pvrtc",
+    "GL_EXT_framebuffer_blit",
+    "GL_ANGLE_framebuffer_blit",
+    "GL_EXT_framebuffer_multisample",
+    "GL_ANGLE_framebuffer_multisample",
+    "GL_OES_rgb8_rgba8",
+    "GL_ARB_robustness",
+    "GL_EXT_robustness",
+    "GL_ARB_sync",
+    "GL_OES_EGL_image",
+    "GL_OES_EGL_sync",
+    "GL_OES_EGL_image_external",
+    "GL_EXT_packed_depth_stencil",
+    "GL_OES_element_index_uint",
+    "GL_OES_vertex_array_object",
+    "GL_ARB_vertex_array_object",
+    "GL_APPLE_vertex_array_object",
+    "GL_ARB_draw_buffers",
+    "GL_EXT_draw_buffers",
+    "GL_EXT_gpu_shader4",
+    "GL_EXT_blend_minmax",
+    "GL_ARB_draw_instanced",
+    "GL_EXT_draw_instanced",
+    "GL_NV_draw_instanced",
+    "GL_ARB_instanced_arrays",
+    "GL_NV_instanced_arrays",
+    "GL_ANGLE_instanced_arrays",
+    "GL_EXT_occlusion_query_boolean",
+    "GL_ARB_occlusion_query2",
+    "GL_EXT_transform_feedback",
+    "GL_NV_transform_feedback",
+    "GL_ANGLE_depth_texture",
+    "GL_EXT_sRGB",
+    "GL_EXT_texture_sRGB",
+    "GL_ARB_framebuffer_sRGB",
+    "GL_EXT_framebuffer_sRGB",
+    "GL_KHR_debug",
+    "GL_ARB_half_float_pixel",
+    "GL_EXT_frag_depth",
+    "GL_OES_compressed_ETC1_RGB8_texture",
+    "GL_EXT_draw_range_elements",
+    nullptr
+};
+
+static bool
+ParseGLVersion(GLContext* gl, unsigned int* version)
+{
+    GLenum error = gl->fGetError();
+    if (error != LOCAL_GL_NO_ERROR) {
+        MOZ_ASSERT(false, "An OpenGL error has been triggered before.");
+        return false;
+    }
+
+    /**
+     * B2G emulator bug work around: The emulator implements OpenGL ES 2.0 on
+     * OpenGL 3.2. The bug is that GetIntegerv(LOCAL_GL_{MAJOR,MINOR}_VERSION)
+     * returns OpenGL 3.2 instead of generating an error.
+     */
+    if (!gl->IsGLES())
+    {
+        /**
+         * OpenGL 3.1 and OpenGL ES 3.0 both introduce GL_{MAJOR,MINOR}_VERSION
+         * with GetIntegerv. So we first try those constants even though we
+         * might not have an OpenGL context supporting them, has this is a
+         * better way than parsing GL_VERSION.
+         */
+        GLint majorVersion = 0;
+        GLint minorVersion = 0;
+
+        gl->fGetIntegerv(LOCAL_GL_MAJOR_VERSION, &majorVersion);
+        gl->fGetIntegerv(LOCAL_GL_MINOR_VERSION, &minorVersion);
+
+        // If it's not an OpenGL (ES) 3.0 context, we will have an error
+        error = gl->fGetError();
+        if (error == LOCAL_GL_NO_ERROR &&
+            majorVersion > 0 &&
+            minorVersion >= 0)
+        {
+            *version = majorVersion * 100 + minorVersion * 10;
+            return true;
+        }
+    }
+
+    /**
+     * We were not able to use GL_{MAJOR,MINOR}_VERSION, so we parse
+     * GL_VERSION.
+     *
+     *
+     * OpenGL 2.x, 3.x, 4.x specifications:
+     *  The VERSION and SHADING_LANGUAGE_VERSION strings are laid out as follows:
+     *
+     *    <version number><space><vendor-specific information>
+     *
+     *  The version number is either of the form major_number.minor_number or
+     *  major_number.minor_number.release_number, where the numbers all have
+     *  one or more digits.
+     *
+     *
+     * OpenGL ES 2.0, 3.0 specifications:
+     *  The VERSION string is laid out as follows:
+     *
+     *     "OpenGL ES N.M vendor-specific information"
+     *
+     *  The version number is either of the form major_number.minor_number or
+     *  major_number.minor_number.release_number, where the numbers all have
+     *  one or more digits.
+     *
+     *
+     * Note:
+     *  We don't care about release_number.
+     */
+    const char* versionString = (const char*)gl->fGetString(LOCAL_GL_VERSION);
+
+    error = gl->fGetError();
+    if (error != LOCAL_GL_NO_ERROR) {
+        MOZ_ASSERT(false, "glGetString(GL_VERSION) has generated an error");
+        return false;
+    } else if (!versionString) {
+        MOZ_ASSERT(false, "glGetString(GL_VERSION) has returned 0");
+        return false;
+    }
+
+    const char kGLESVersionPrefix[] = "OpenGL ES ";
+    if (strncmp(versionString, kGLESVersionPrefix, strlen(kGLESVersionPrefix)) == 0) {
+        versionString += strlen(kGLESVersionPrefix);
+    }
+
+    const char* itr = versionString;
+    char* end = nullptr;
+    int majorVersion = (int)strtol(itr, &end, 10);
+
+    if (!end) {
+        MOZ_ASSERT(false, "Failed to parse the GL major version number.");
+        return false;
+    } else if (*end != '.') {
+        MOZ_ASSERT(false, "Failed to parse GL's major-minor version number separator.");
+        return false;
+    }
+
+    // we skip the '.' between the major and the minor version
+    itr = end + 1;
+
+    end = nullptr;
+
+    int minorVersion = (int)strtol(itr, &end, 10);
+    if (!end) {
+        MOZ_ASSERT(false, "Failed to parse GL's minor version number.");
+        return false;
+    }
+
+    if (majorVersion <= 0 || majorVersion >= 100) {
+        MOZ_ASSERT(false, "Invalid major version.");
+        return false;
+    } else if (minorVersion < 0 || minorVersion >= 10) {
+        MOZ_ASSERT(false, "Invalid minor version.");
+        return false;
+    }
+
+    *version = (unsigned int)(majorVersion * 100 + minorVersion * 10);
+    return true;
+}
+
+GLContext::GLContext(const SurfaceCaps& caps,
+          GLContext* sharedContext,
+          bool isOffscreen)
+  : mInitialized(false),
+    mIsOffscreen(isOffscreen),
+    mContextLost(false),
+    mVersion(0),
+    mProfile(ContextProfile::Unknown),
+    mVendor(GLVendor::Other),
+    mRenderer(GLRenderer::Other),
+    mHasRobustness(false),
+#ifdef DEBUG
+    mGLError(LOCAL_GL_NO_ERROR),
+#endif
+    mSharedContext(sharedContext),
+    mCaps(caps),
+    mScreen(nullptr),
+    mLockedSurface(nullptr),
+    mMaxTextureSize(0),
+    mMaxCubeMapTextureSize(0),
+    mMaxTextureImageSize(0),
+    mMaxRenderbufferSize(0),
+    mNeedsTextureSizeChecks(false),
+    mWorkAroundDriverBugs(true)
+{
+    mOwningThread = NS_GetCurrentThread();
+}
+
+GLContext::~GLContext() {
+    NS_ASSERTION(IsDestroyed(), "GLContext implementation must call MarkDestroyed in destructor!");
+#ifdef DEBUG
+    if (mSharedContext) {
+        GLContext *tip = mSharedContext;
+        while (tip->mSharedContext)
+            tip = tip->mSharedContext;
+        tip->SharedContextDestroyed(this);
+        tip->ReportOutstandingNames();
+    } else {
+        ReportOutstandingNames();
+    }
+#endif
+}
+
+bool
+GLContext::InitWithPrefix(const char *prefix, bool trygl)
+{
+    ScopedGfxFeatureReporter reporter("GL Context");
+
+    if (mInitialized) {
+        reporter.SetSuccessful();
+        return true;
+    }
+
+    mWorkAroundDriverBugs = gfxPrefs::WorkAroundDriverBugs();
+
+    SymLoadStruct symbols[] = {
+        { (PRFuncPtr*) &mSymbols.fActiveTexture, { "ActiveTexture", "ActiveTextureARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fAttachShader, { "AttachShader", "AttachShaderARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBindAttribLocation, { "BindAttribLocation", "BindAttribLocationARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBindBuffer, { "BindBuffer", "BindBufferARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBindTexture, { "BindTexture", "BindTextureARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBlendColor, { "BlendColor", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBlendEquation, { "BlendEquation", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBlendEquationSeparate, { "BlendEquationSeparate", "BlendEquationSeparateEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBlendFunc, { "BlendFunc", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBlendFuncSeparate, { "BlendFuncSeparate", "BlendFuncSeparateEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBufferData, { "BufferData", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBufferSubData, { "BufferSubData", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fClear, { "Clear", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fClearColor, { "ClearColor", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fClearStencil, { "ClearStencil", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fColorMask, { "ColorMask", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCompressedTexImage2D, {"CompressedTexImage2D", nullptr} },
+        { (PRFuncPtr*) &mSymbols.fCompressedTexSubImage2D, {"CompressedTexSubImage2D", nullptr} },
+        { (PRFuncPtr*) &mSymbols.fCullFace, { "CullFace", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDetachShader, { "DetachShader", "DetachShaderARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDepthFunc, { "DepthFunc", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDepthMask, { "DepthMask", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDisable, { "Disable", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDisableVertexAttribArray, { "DisableVertexAttribArray", "DisableVertexAttribArrayARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDrawArrays, { "DrawArrays", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDrawElements, { "DrawElements", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fEnable, { "Enable", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fEnableVertexAttribArray, { "EnableVertexAttribArray", "EnableVertexAttribArrayARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fFinish, { "Finish", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fFlush, { "Flush", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fFrontFace, { "FrontFace", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetActiveAttrib, { "GetActiveAttrib", "GetActiveAttribARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetActiveUniform, { "GetActiveUniform", "GetActiveUniformARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetAttachedShaders, { "GetAttachedShaders", "GetAttachedShadersARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetAttribLocation, { "GetAttribLocation", "GetAttribLocationARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetIntegerv, { "GetIntegerv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetFloatv, { "GetFloatv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetBooleanv, { "GetBooleanv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetBufferParameteriv, { "GetBufferParameteriv", "GetBufferParameterivARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetError, { "GetError", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetProgramiv, { "GetProgramiv", "GetProgramivARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetProgramInfoLog, { "GetProgramInfoLog", "GetProgramInfoLogARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fTexParameteri, { "TexParameteri", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fTexParameteriv, { "TexParameteriv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fTexParameterf, { "TexParameterf", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetString, { "GetString", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetTexParameterfv, { "GetTexParameterfv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetTexParameteriv, { "GetTexParameteriv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetUniformfv, { "GetUniformfv", "GetUniformfvARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetUniformiv, { "GetUniformiv", "GetUniformivARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetUniformLocation, { "GetUniformLocation", "GetUniformLocationARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetVertexAttribfv, { "GetVertexAttribfv", "GetVertexAttribfvARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetVertexAttribiv, { "GetVertexAttribiv", "GetVertexAttribivARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetVertexAttribPointerv, { "GetVertexAttribPointerv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fHint, { "Hint", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsBuffer, { "IsBuffer", "IsBufferARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsEnabled, { "IsEnabled", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsProgram, { "IsProgram", "IsProgramARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsShader, { "IsShader", "IsShaderARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsTexture, { "IsTexture", "IsTextureARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fLineWidth, { "LineWidth", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fLinkProgram, { "LinkProgram", "LinkProgramARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fPixelStorei, { "PixelStorei", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fPolygonOffset, { "PolygonOffset", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fReadPixels, { "ReadPixels", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fSampleCoverage, { "SampleCoverage", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fScissor, { "Scissor", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fStencilFunc, { "StencilFunc", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fStencilFuncSeparate, { "StencilFuncSeparate", "StencilFuncSeparateEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fStencilMask, { "StencilMask", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fStencilMaskSeparate, { "StencilMaskSeparate", "StencilMaskSeparateEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fStencilOp, { "StencilOp", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fStencilOpSeparate, { "StencilOpSeparate", "StencilOpSeparateEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fTexImage2D, { "TexImage2D", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fTexSubImage2D, { "TexSubImage2D", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform1f, { "Uniform1f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform1fv, { "Uniform1fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform1i, { "Uniform1i", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform1iv, { "Uniform1iv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform2f, { "Uniform2f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform2fv, { "Uniform2fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform2i, { "Uniform2i", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform2iv, { "Uniform2iv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform3f, { "Uniform3f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform3fv, { "Uniform3fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform3i, { "Uniform3i", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform3iv, { "Uniform3iv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform4f, { "Uniform4f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform4fv, { "Uniform4fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform4i, { "Uniform4i", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniform4iv, { "Uniform4iv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniformMatrix2fv, { "UniformMatrix2fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniformMatrix3fv, { "UniformMatrix3fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUniformMatrix4fv, { "UniformMatrix4fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fUseProgram, { "UseProgram", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fValidateProgram, { "ValidateProgram", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttribPointer, { "VertexAttribPointer", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib1f, { "VertexAttrib1f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib2f, { "VertexAttrib2f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib3f, { "VertexAttrib3f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib4f, { "VertexAttrib4f", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib1fv, { "VertexAttrib1fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib2fv, { "VertexAttrib2fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib3fv, { "VertexAttrib3fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttrib4fv, { "VertexAttrib4fv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fViewport, { "Viewport", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCompileShader, { "CompileShader", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCopyTexImage2D, { "CopyTexImage2D", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCopyTexSubImage2D, { "CopyTexSubImage2D", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetShaderiv, { "GetShaderiv", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetShaderInfoLog, { "GetShaderInfoLog", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetShaderSource, { "GetShaderSource", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fShaderSource, { "ShaderSource", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fVertexAttribPointer, { "VertexAttribPointer", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBindFramebuffer, { "BindFramebuffer", "BindFramebufferEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fBindRenderbuffer, { "BindRenderbuffer", "BindRenderbufferEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCheckFramebufferStatus, { "CheckFramebufferStatus", "CheckFramebufferStatusEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fFramebufferRenderbuffer, { "FramebufferRenderbuffer", "FramebufferRenderbufferEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fFramebufferTexture2D, { "FramebufferTexture2D", "FramebufferTexture2DEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGenerateMipmap, { "GenerateMipmap", "GenerateMipmapEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetFramebufferAttachmentParameteriv, { "GetFramebufferAttachmentParameteriv", "GetFramebufferAttachmentParameterivEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGetRenderbufferParameteriv, { "GetRenderbufferParameteriv", "GetRenderbufferParameterivEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsFramebuffer, { "IsFramebuffer", "IsFramebufferEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fIsRenderbuffer, { "IsRenderbuffer", "IsRenderbufferEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fRenderbufferStorage, { "RenderbufferStorage", "RenderbufferStorageEXT", nullptr } },
+
+        { (PRFuncPtr*) &mSymbols.fGenBuffers, { "GenBuffers", "GenBuffersARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGenTextures, { "GenTextures", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCreateProgram, { "CreateProgram", "CreateProgramARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fCreateShader, { "CreateShader", "CreateShaderARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGenFramebuffers, { "GenFramebuffers", "GenFramebuffersEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fGenRenderbuffers, { "GenRenderbuffers", "GenRenderbuffersEXT", nullptr } },
+
+        { (PRFuncPtr*) &mSymbols.fDeleteBuffers, { "DeleteBuffers", "DeleteBuffersARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDeleteTextures, { "DeleteTextures", "DeleteTexturesARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDeleteProgram, { "DeleteProgram", "DeleteProgramARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDeleteShader, { "DeleteShader", "DeleteShaderARB", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDeleteFramebuffers, { "DeleteFramebuffers", "DeleteFramebuffersEXT", nullptr } },
+        { (PRFuncPtr*) &mSymbols.fDeleteRenderbuffers, { "DeleteRenderbuffers", "DeleteRenderbuffersEXT", nullptr } },
+
+        { nullptr, { nullptr } },
+
+    };
+
+    mInitialized = LoadSymbols(&symbols[0], trygl, prefix);
+    MakeCurrent();
+    if (mInitialized) {
+        unsigned int version = 0;
+
+        ParseGLVersion(this, &version);
+
+#ifdef DEBUG
+        printf_stderr("OpenGL version detected: %u\n", version);
+        printf_stderr("OpenGL vendor: %s\n", fGetString(LOCAL_GL_VENDOR));
+        printf_stderr("OpenGL renderer: %s\n", fGetString(LOCAL_GL_RENDERER));
+#endif
+
+        if (version >= mVersion) {
+            mVersion = version;
+        }
+        // Don't fail if version < mVersion, see bug 999445,
+        // Mac OSX 10.6/10.7 machines with Intel GPUs claim only OpenGL 1.4 but
+        // have all the GL2+ extensions that we need.
+    }
+
+    // Load OpenGL ES 2.0 symbols, or desktop if we aren't using ES 2.
+    if (mInitialized) {
+        if (IsGLES()) {
+            SymLoadStruct symbols_ES2[] = {
+                { (PRFuncPtr*) &mSymbols.fGetShaderPrecisionFormat, { "GetShaderPrecisionFormat", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fClearDepthf, { "ClearDepthf", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDepthRangef, { "DepthRangef", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&symbols_ES2[0], trygl, prefix)) {
+                NS_ERROR("OpenGL ES 2.0 supported, but symbols could not be loaded.");
+                mInitialized = false;
+            }
+        } else {
+            SymLoadStruct symbols_desktop[] = {
+                { (PRFuncPtr*) &mSymbols.fClearDepth, { "ClearDepth", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDepthRange, { "DepthRange", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fReadBuffer, { "ReadBuffer", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fMapBuffer, { "MapBuffer", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fUnmapBuffer, { "UnmapBuffer", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fPointParameterf, { "PointParameterf", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDrawBuffer, { "DrawBuffer", nullptr } },
+                    // These functions are only used by Skia/GL in desktop mode.
+                    // Other parts of Gecko should avoid using these
+                    { (PRFuncPtr*) &mSymbols.fDrawBuffers, { "DrawBuffers", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fClientActiveTexture, { "ClientActiveTexture", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fDisableClientState, { "DisableClientState", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fEnableClientState, { "EnableClientState", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fLoadIdentity, { "LoadIdentity", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fLoadMatrixf, { "LoadMatrixf", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fMatrixMode, { "MatrixMode", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fTexGeni, { "TexGeni", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fTexGenf, { "TexGenf", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fTexGenfv, { "TexGenfv", nullptr } },
+                    { (PRFuncPtr*) &mSymbols.fVertexPointer, { "VertexPointer", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&symbols_desktop[0], trygl, prefix)) {
+                NS_ERROR("Desktop symbols failed to load.");
+                mInitialized = false;
+            }
+        }
+    }
+
+    const char *glVendorString = nullptr;
+    const char *glRendererString = nullptr;
+
+    if (mInitialized) {
+        // The order of these strings must match up with the order of the enum
+        // defined in GLContext.h for vendor IDs
+        glVendorString = (const char *)fGetString(LOCAL_GL_VENDOR);
+        if (!glVendorString)
+            mInitialized = false;
+
+        const char *vendorMatchStrings[size_t(GLVendor::Other)] = {
+                "Intel",
+                "NVIDIA",
+                "ATI",
+                "Qualcomm",
+                "Imagination",
+                "nouveau",
+                "Vivante",
+                "VMware, Inc."
+        };
+
+        mVendor = GLVendor::Other;
+        for (size_t i = 0; i < size_t(GLVendor::Other); ++i) {
+            if (DoesStringMatch(glVendorString, vendorMatchStrings[i])) {
+                mVendor = GLVendor(i);
+                break;
+            }
+        }
+
+        // The order of these strings must match up with the order of the enum
+        // defined in GLContext.h for renderer IDs
+        glRendererString = (const char *)fGetString(LOCAL_GL_RENDERER);
+        if (!glRendererString)
+            mInitialized = false;
+
+        const char *rendererMatchStrings[size_t(GLRenderer::Other)] = {
+                "Adreno 200",
+                "Adreno 205",
+                "Adreno (TM) 205",
+                "Adreno (TM) 320",
+                "PowerVR SGX 530",
+                "PowerVR SGX 540",
+                "NVIDIA Tegra",
+                "Android Emulator",
+                "Gallium 0.4 on llvmpipe"
+        };
+
+        mRenderer = GLRenderer::Other;
+        for (size_t i = 0; i < size_t(GLRenderer::Other); ++i) {
+            if (DoesStringMatch(glRendererString, rendererMatchStrings[i])) {
+                mRenderer = GLRenderer(i);
+                break;
+            }
+        }
+    }
+
+
+#ifdef DEBUG
+    if (PR_GetEnv("MOZ_GL_DEBUG"))
+        sDebugMode |= DebugEnabled;
+
+    // enables extra verbose output, informing of the start and finish of every GL call.
+    // useful e.g. to record information to investigate graphics system crashes/lockups
+    if (PR_GetEnv("MOZ_GL_DEBUG_VERBOSE"))
+        sDebugMode |= DebugTrace;
+
+    // aborts on GL error. Can be useful to debug quicker code that is known not to generate any GL error in principle.
+    if (PR_GetEnv("MOZ_GL_DEBUG_ABORT_ON_ERROR"))
+        sDebugMode |= DebugAbortOnError;
+#endif
+
+    if (mInitialized) {
+#ifdef DEBUG
+        static bool firstRun = true;
+        if (firstRun && DebugMode()) {
+            const char *vendors[size_t(GLVendor::Other)] = {
+                "Intel",
+                "NVIDIA",
+                "ATI",
+                "Qualcomm"
+            };
+
+            MOZ_ASSERT(glVendorString);
+            if (mVendor < GLVendor::Other) {
+                printf_stderr("OpenGL vendor ('%s') recognized as: %s\n",
+                              glVendorString, vendors[size_t(mVendor)]);
+            } else {
+                printf_stderr("OpenGL vendor ('%s') unrecognized\n", glVendorString);
+            }
+        }
+        firstRun = false;
+#endif
+
+        InitExtensions();
+        InitFeatures();
+
+        // Disable extensions with partial or incorrect support.
+        if (WorkAroundDriverBugs()) {
+            if (Renderer() == GLRenderer::AdrenoTM320) {
+                MarkUnsupported(GLFeature::standard_derivatives);
+            }
+
+            if (Vendor() == GLVendor::Vivante) {
+                // bug 958256
+                MarkUnsupported(GLFeature::standard_derivatives);
+            }
+
+            if (Vendor() == GLVendor::Imagination &&
+                Renderer() == GLRenderer::SGX540) {
+                // Bug 980048
+                MarkExtensionUnsupported(OES_EGL_sync);
+            }
+
+#ifdef XP_MACOSX
+            // The Mac Nvidia driver, for versions up to and including 10.8, don't seem
+            // to properly support this.  See 814839
+            // this has been fixed in Mac OS X 10.9. See 907946
+            if (Vendor() == gl::GLVendor::NVIDIA &&
+                !nsCocoaFeatures::OnMavericksOrLater())
+            {
+                MarkUnsupported(GLFeature::depth_texture);
+            }
+#endif
+            // ANGLE's divisor support is busted. (see bug 916816)
+            if (IsANGLE()) {
+                MarkUnsupported(GLFeature::instanced_arrays);
+            }
+        }
+
+        NS_ASSERTION(!IsExtensionSupported(GLContext::ARB_pixel_buffer_object) ||
+                     (mSymbols.fMapBuffer && mSymbols.fUnmapBuffer),
+                     "ARB_pixel_buffer_object supported without glMapBuffer/UnmapBuffer being available!");
+
+        if (SupportsRobustness()) {
+            mHasRobustness = false;
+
+            if (IsExtensionSupported(ARB_robustness)) {
+                SymLoadStruct robustnessSymbols[] = {
+                    { (PRFuncPtr*) &mSymbols.fGetGraphicsResetStatus, { "GetGraphicsResetStatusARB", nullptr } },
+                    { nullptr, { nullptr } },
+                };
+
+                if (!LoadSymbols(&robustnessSymbols[0], trygl, prefix)) {
+                    NS_ERROR("GL supports ARB_robustness without supplying GetGraphicsResetStatusARB.");
+
+                    mSymbols.fGetGraphicsResetStatus = nullptr;
+                } else {
+                    mHasRobustness = true;
+                }
+            }
+            if (!IsExtensionSupported(ARB_robustness) &&
+                IsExtensionSupported(EXT_robustness)) {
+                SymLoadStruct robustnessSymbols[] = {
+                    { (PRFuncPtr*) &mSymbols.fGetGraphicsResetStatus, { "GetGraphicsResetStatusEXT", nullptr } },
+                    { nullptr, { nullptr } },
+                };
+
+                if (!LoadSymbols(&robustnessSymbols[0], trygl, prefix)) {
+                    NS_ERROR("GL supports EXT_robustness without supplying GetGraphicsResetStatusEXT.");
+
+                    mSymbols.fGetGraphicsResetStatus = nullptr;
+                } else {
+                    mHasRobustness = true;
+                }
+            }
+
+            if (!mHasRobustness) {
+                MarkUnsupported(GLFeature::robustness);
+            }
+        }
+
+        // Check for aux symbols based on extensions
+        if (IsSupported(GLFeature::framebuffer_blit))
+        {
+            SymLoadStruct auxSymbols[] = {
+                {
+                    (PRFuncPtr*) &mSymbols.fBlitFramebuffer,
+                    {
+                        "BlitFramebuffer",
+                        "BlitFramebufferEXT",
+                        "BlitFramebufferANGLE",
+                        nullptr
+                    }
+                },
+                { nullptr, { nullptr } },
+            };
+            if (!LoadSymbols(&auxSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports framebuffer_blit without supplying glBlitFramebuffer");
+
+                MarkUnsupported(GLFeature::framebuffer_blit);
+                mSymbols.fBlitFramebuffer = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::framebuffer_multisample))
+        {
+            SymLoadStruct auxSymbols[] = {
+                {
+                    (PRFuncPtr*) &mSymbols.fRenderbufferStorageMultisample,
+                    {
+                        "RenderbufferStorageMultisample",
+                        "RenderbufferStorageMultisampleEXT",
+                        "RenderbufferStorageMultisampleANGLE",
+                        nullptr
+                    }
+                },
+                { nullptr, { nullptr } },
+            };
+            if (!LoadSymbols(&auxSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports framebuffer_multisample without supplying glRenderbufferStorageMultisample");
+
+                MarkUnsupported(GLFeature::framebuffer_multisample);
+                mSymbols.fRenderbufferStorageMultisample = nullptr;
+            }
+        }
+
+        if (IsExtensionSupported(ARB_sync)) {
+            SymLoadStruct syncSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fFenceSync,      { "FenceSync",      nullptr } },
+                { (PRFuncPtr*) &mSymbols.fIsSync,         { "IsSync",         nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDeleteSync,     { "DeleteSync",     nullptr } },
+                { (PRFuncPtr*) &mSymbols.fClientWaitSync, { "ClientWaitSync", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fWaitSync,       { "WaitSync",       nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetInteger64v,  { "GetInteger64v",  nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetSynciv,      { "GetSynciv",      nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&syncSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports ARB_sync without supplying its functions.");
+
+                MarkExtensionUnsupported(ARB_sync);
+                mSymbols.fFenceSync = nullptr;
+                mSymbols.fIsSync = nullptr;
+                mSymbols.fDeleteSync = nullptr;
+                mSymbols.fClientWaitSync = nullptr;
+                mSymbols.fWaitSync = nullptr;
+                mSymbols.fGetInteger64v = nullptr;
+                mSymbols.fGetSynciv = nullptr;
+            }
+        }
+
+        if (IsExtensionSupported(OES_EGL_image)) {
+            SymLoadStruct imageSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fEGLImageTargetTexture2D, { "EGLImageTargetTexture2DOES", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fEGLImageTargetRenderbufferStorage, { "EGLImageTargetRenderbufferStorageOES", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&imageSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports OES_EGL_image without supplying its functions.");
+
+                MarkExtensionUnsupported(OES_EGL_image);
+                mSymbols.fEGLImageTargetTexture2D = nullptr;
+                mSymbols.fEGLImageTargetRenderbufferStorage = nullptr;
+            }
+        }
+
+        if (IsExtensionSupported(APPLE_texture_range)) {
+            SymLoadStruct vaoSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fTextureRangeAPPLE, { "TextureRangeAPPLE", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&vaoSymbols[0], trygl, prefix)) {
+                mSymbols.fTextureRangeAPPLE = nullptr;
+            }
+        }
+
+        if (IsExtensionSupported(ARB_vertex_array_object) ||
+            IsExtensionSupported(OES_vertex_array_object)) {
+            SymLoadStruct vaoSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fIsVertexArray, { "IsVertexArray", "IsVertexArrayOES", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGenVertexArrays, { "GenVertexArrays", "GenVertexArraysOES", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fBindVertexArray, { "BindVertexArray", "BindVertexArrayOES", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDeleteVertexArrays, { "DeleteVertexArrays", "DeleteVertexArraysOES", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&vaoSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports Vertex Array Object without supplying its functions.");
+
+                MarkUnsupported(GLFeature::vertex_array_object);
+                mSymbols.fIsVertexArray = nullptr;
+                mSymbols.fGenVertexArrays = nullptr;
+                mSymbols.fBindVertexArray = nullptr;
+                mSymbols.fDeleteVertexArrays = nullptr;
+            }
+        }
+        else if (IsExtensionSupported(APPLE_vertex_array_object)) {
+            /*
+             * separate call to LoadSymbols with APPLE_vertex_array_object to work around
+             * a driver bug : the IsVertexArray symbol (without suffix) can be present but unusable.
+             */
+            SymLoadStruct vaoSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fIsVertexArray, { "IsVertexArrayAPPLE", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGenVertexArrays, { "GenVertexArraysAPPLE", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fBindVertexArray, { "BindVertexArrayAPPLE", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDeleteVertexArrays, { "DeleteVertexArraysAPPLE", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&vaoSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports Vertex Array Object without supplying its functions.");
+
+                MarkUnsupported(GLFeature::vertex_array_object);
+                mSymbols.fIsVertexArray = nullptr;
+                mSymbols.fGenVertexArrays = nullptr;
+                mSymbols.fBindVertexArray = nullptr;
+                mSymbols.fDeleteVertexArrays = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::draw_instanced)) {
+            SymLoadStruct drawInstancedSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fDrawArraysInstanced,
+                  { "DrawArraysInstanced",
+                    "DrawArraysInstancedARB",
+                    "DrawArraysInstancedEXT",
+                    "DrawArraysInstancedNV",
+                    "DrawArraysInstancedANGLE",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fDrawElementsInstanced,
+                  { "DrawElementsInstanced",
+                    "DrawElementsInstancedARB",
+                    "DrawElementsInstancedEXT",
+                    "DrawElementsInstancedNV",
+                    "DrawElementsInstancedANGLE",
+                    nullptr
+                  }
+                },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(drawInstancedSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports instanced draws without supplying its functions.");
+
+                MarkUnsupported(GLFeature::draw_instanced);
+                mSymbols.fDrawArraysInstanced = nullptr;
+                mSymbols.fDrawElementsInstanced = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::instanced_arrays)) {
+            SymLoadStruct instancedArraySymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fVertexAttribDivisor,
+                  { "VertexAttribDivisor",
+                    "VertexAttribDivisorARB",
+                    "VertexAttribDivisorNV",
+                    "VertexAttribDivisorANGLE",
+                    nullptr
+                  }
+                },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(instancedArraySymbols, trygl, prefix)) {
+                NS_ERROR("GL supports array instanced without supplying it function.");
+
+                MarkUnsupported(GLFeature::instanced_arrays);
+                mSymbols.fVertexAttribDivisor = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::transform_feedback)) {
+            SymLoadStruct transformFeedbackSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fBindBufferBase,
+                  { "BindBufferBase",
+                    "BindBufferBaseEXT",
+                    "BindBufferBaseNV",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fBindBufferRange,
+                  { "BindBufferRange",
+                    "BindBufferRangeEXT",
+                    "BindBufferRangeNV",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fBeginTransformFeedback,
+                  { "BeginTransformFeedback",
+                    "BeginTransformFeedbackEXT",
+                    "BeginTransformFeedbackNV",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fEndTransformFeedback,
+                  { "EndTransformFeedback",
+                    "EndTransformFeedbackEXT",
+                    "EndTransformFeedbackNV",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fTransformFeedbackVaryings,
+                  { "TransformFeedbackVaryings",
+                    "TransformFeedbackVaryingsEXT",
+                    "TransformFeedbackVaryingsNV",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fGetTransformFeedbackVarying,
+                  { "GetTransformFeedbackVarying",
+                    "GetTransformFeedbackVaryingEXT",
+                    "GetTransformFeedbackVaryingNV",
+                    nullptr
+                  }
+                },
+                { (PRFuncPtr*) &mSymbols.fGetIntegeri_v,
+                  { "GetIntegeri_v",
+                    "GetIntegerIndexedvEXT",
+                    "GetIntegerIndexedvNV",
+                    nullptr
+                  }
+                },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(transformFeedbackSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports transform feedback without supplying its functions.");
+
+                MarkUnsupported(GLFeature::transform_feedback);
+                MarkUnsupported(GLFeature::bind_buffer_offset);
+                mSymbols.fBindBufferBase = nullptr;
+                mSymbols.fBindBufferRange = nullptr;
+                mSymbols.fBeginTransformFeedback = nullptr;
+                mSymbols.fEndTransformFeedback = nullptr;
+                mSymbols.fTransformFeedbackVaryings = nullptr;
+                mSymbols.fGetTransformFeedbackVarying = nullptr;
+                mSymbols.fGetIntegeri_v = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::bind_buffer_offset)) {
+            SymLoadStruct bindBufferOffsetSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fBindBufferOffset,
+                  { "BindBufferOffset",
+                    "BindBufferOffsetEXT",
+                    "BindBufferOffsetNV",
+                    nullptr
+                  }
+                },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(bindBufferOffsetSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports BindBufferOffset without supplying its function.");
+
+                MarkUnsupported(GLFeature::bind_buffer_offset);
+                mSymbols.fBindBufferOffset = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::query_objects)) {
+            SymLoadStruct queryObjectsSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fBeginQuery, { "BeginQuery", "BeginQueryEXT", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGenQueries, { "GenQueries", "GenQueriesEXT", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDeleteQueries, { "DeleteQueries", "DeleteQueriesEXT", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fEndQuery, { "EndQuery", "EndQueryEXT", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetQueryiv, { "GetQueryiv", "GetQueryivEXT", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetQueryObjectuiv, { "GetQueryObjectuiv", "GetQueryObjectuivEXT", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fIsQuery, { "IsQuery", "IsQueryEXT", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(queryObjectsSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports query objects without supplying its functions.");
+
+                MarkUnsupported(GLFeature::query_objects);
+                MarkUnsupported(GLFeature::get_query_object_iv);
+                MarkUnsupported(GLFeature::occlusion_query);
+                MarkUnsupported(GLFeature::occlusion_query_boolean);
+                MarkUnsupported(GLFeature::occlusion_query2);
+                mSymbols.fBeginQuery = nullptr;
+                mSymbols.fGenQueries = nullptr;
+                mSymbols.fDeleteQueries = nullptr;
+                mSymbols.fEndQuery = nullptr;
+                mSymbols.fGetQueryiv = nullptr;
+                mSymbols.fGetQueryObjectuiv = nullptr;
+                mSymbols.fIsQuery = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::get_query_object_iv)) {
+            SymLoadStruct queryObjectsSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fGetQueryObjectiv, { "GetQueryObjectiv", "GetQueryObjectivEXT", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(queryObjectsSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports query objects iv getter without supplying its function.");
+
+                MarkUnsupported(GLFeature::get_query_object_iv);
+                mSymbols.fGetQueryObjectiv = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::draw_buffers)) {
+            SymLoadStruct drawBuffersSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fDrawBuffers, { "DrawBuffers", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(drawBuffersSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports draw_buffers without supplying its functions.");
+
+                MarkUnsupported(GLFeature::draw_buffers);
+                mSymbols.fDrawBuffers = nullptr;
+            }
+        }
+
+        if (IsExtensionSupported(KHR_debug)) {
+            SymLoadStruct extSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fDebugMessageControl,  { "DebugMessageControl",  "DebugMessageControlKHR",  nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDebugMessageInsert,   { "DebugMessageInsert",   "DebugMessageInsertKHR",   nullptr } },
+                { (PRFuncPtr*) &mSymbols.fDebugMessageCallback, { "DebugMessageCallback", "DebugMessageCallbackKHR", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetDebugMessageLog,   { "GetDebugMessageLog",   "GetDebugMessageLogKHR",   nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetPointerv,          { "GetPointerv",          "GetPointervKHR",          nullptr } },
+                { (PRFuncPtr*) &mSymbols.fPushDebugGroup,       { "PushDebugGroup",       "PushDebugGroupKHR",       nullptr } },
+                { (PRFuncPtr*) &mSymbols.fPopDebugGroup,        { "PopDebugGroup",        "PopDebugGroupKHR",        nullptr } },
+                { (PRFuncPtr*) &mSymbols.fObjectLabel,          { "ObjectLabel",          "ObjectLabelKHR",          nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetObjectLabel,       { "GetObjectLabel",       "GetObjectLabelKHR",       nullptr } },
+                { (PRFuncPtr*) &mSymbols.fObjectPtrLabel,       { "ObjectPtrLabel",       "ObjectPtrLabelKHR",       nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetObjectPtrLabel,    { "GetObjectPtrLabel",    "GetObjectPtrLabelKHR",    nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&extSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports KHR_debug without supplying its functions.");
+
+                MarkExtensionUnsupported(KHR_debug);
+                mSymbols.fDebugMessageControl  = nullptr;
+                mSymbols.fDebugMessageInsert   = nullptr;
+                mSymbols.fDebugMessageCallback = nullptr;
+                mSymbols.fGetDebugMessageLog   = nullptr;
+                mSymbols.fGetPointerv          = nullptr;
+                mSymbols.fPushDebugGroup       = nullptr;
+                mSymbols.fPopDebugGroup        = nullptr;
+                mSymbols.fObjectLabel          = nullptr;
+                mSymbols.fGetObjectLabel       = nullptr;
+                mSymbols.fObjectPtrLabel       = nullptr;
+                mSymbols.fGetObjectPtrLabel    = nullptr;
+            }
+        }
+
+        if (IsSupported(GLFeature::draw_range_elements)) {
+            SymLoadStruct imageSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fDrawRangeElements, { "DrawRangeElementsEXT", "DrawRangeElements", nullptr } },
+                { nullptr, { nullptr } },
+            };
+
+            if (!LoadSymbols(&imageSymbols[0], trygl, prefix)) {
+                NS_ERROR("GL supports draw_range_elements without supplying its functions.");
+
+                MarkUnsupported(GLFeature::draw_range_elements);
+                mSymbols.fDrawRangeElements = nullptr;
+            }
+        }
+
+        // Load developer symbols, don't fail if we can't find them.
+        SymLoadStruct auxSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fGetTexImage, { "GetTexImage", nullptr } },
+                { (PRFuncPtr*) &mSymbols.fGetTexLevelParameteriv, { "GetTexLevelParameteriv", nullptr } },
+                { nullptr, { nullptr } },
+        };
+        bool warnOnFailures = DebugMode();
+        LoadSymbols(&auxSymbols[0], trygl, prefix, warnOnFailures);
+    }
+
+    if (mInitialized) {
+        raw_fGetIntegerv(LOCAL_GL_VIEWPORT, mViewportRect);
+        raw_fGetIntegerv(LOCAL_GL_SCISSOR_BOX, mScissorRect);
+        raw_fGetIntegerv(LOCAL_GL_MAX_TEXTURE_SIZE, &mMaxTextureSize);
+        raw_fGetIntegerv(LOCAL_GL_MAX_CUBE_MAP_TEXTURE_SIZE, &mMaxCubeMapTextureSize);
+        raw_fGetIntegerv(LOCAL_GL_MAX_RENDERBUFFER_SIZE, &mMaxRenderbufferSize);
+
+#ifdef XP_MACOSX
+        if (mWorkAroundDriverBugs) {
+            if (mVendor == GLVendor::Intel) {
+                // see bug 737182 for 2D textures, bug 684882 for cube map textures.
+                mMaxTextureSize        = std::min(mMaxTextureSize,        4096);
+                mMaxCubeMapTextureSize = std::min(mMaxCubeMapTextureSize, 512);
+                // for good measure, we align renderbuffers on what we do for 2D textures
+                mMaxRenderbufferSize   = std::min(mMaxRenderbufferSize,   4096);
+                mNeedsTextureSizeChecks = true;
+            } else if (mVendor == GLVendor::NVIDIA) {
+                if (nsCocoaFeatures::OnMountainLionOrLater()) {
+                    // See bug 879656.  8192 fails, 8191 works.
+                    mMaxTextureSize = std::min(mMaxTextureSize, 8191);
+                    mMaxRenderbufferSize = std::min(mMaxRenderbufferSize, 8191);
+                }
+                else {
+                    // See bug 877949.
+                    mMaxTextureSize = std::min(mMaxTextureSize, 4096);
+                    mMaxRenderbufferSize = std::min(mMaxRenderbufferSize, 4096);
+                }
+
+                // Part of the bug 879656, but it also doesn't hurt the 877949
+                mNeedsTextureSizeChecks = true;
+            }
+        }
+#endif
+#ifdef MOZ_X11
+        if (mWorkAroundDriverBugs &&
+            mVendor == GLVendor::Nouveau) {
+            // see bug 814716. Clamp MaxCubeMapTextureSize at 2K for Nouveau.
+            mMaxCubeMapTextureSize = std::min(mMaxCubeMapTextureSize, 2048);
+            mNeedsTextureSizeChecks = true;
+        }
+#endif
+
+        mMaxTextureImageSize = mMaxTextureSize;
+
+        mMaxSamples = 0;
+        if (IsSupported(GLFeature::framebuffer_multisample)) {
+            fGetIntegerv(LOCAL_GL_MAX_SAMPLES, (GLint*)&mMaxSamples);
+        }
+
+        // We're ready for final setup.
+        fBindFramebuffer(LOCAL_GL_FRAMEBUFFER, 0);
+
+        if (mCaps.any)
+            DetermineCaps();
+
+        UpdatePixelFormat();
+        UpdateGLFormats(mCaps);
+
+        mTexGarbageBin = new TextureGarbageBin(this);
+
+        MOZ_ASSERT(IsCurrent());
+    }
+
+    if (mInitialized)
+        reporter.SetSuccessful();
+    else {
+        // if initialization fails, ensure all symbols are zero, to avoid hard-to-understand bugs
+        mSymbols.Zero();
+        NS_WARNING("InitWithPrefix failed!");
+    }
+
+    mVersionString = nsPrintfCString("%u.%u.%u", mVersion / 100, (mVersion / 10) % 10, mVersion % 10);
+
+    return mInitialized;
+}
+
+void
+GLContext::InitExtensions()
+{
+    MakeCurrent();
+    const char* extensions = (const char*)fGetString(LOCAL_GL_EXTENSIONS);
+    if (!extensions)
+        return;
+
+#ifdef DEBUG
+    static bool firstRun = true;
+#else
+    // Non-DEBUG, so never spew.
+    const bool firstRun = false;
+#endif
+
+    InitializeExtensionsBitSet(mAvailableExtensions, extensions, sExtensionNames, firstRun && DebugMode());
+
+    if (WorkAroundDriverBugs() &&
+        Vendor() == GLVendor::Qualcomm) {
+
+        // Some Adreno drivers do not report GL_OES_EGL_sync, but they really do support it.
+        MarkExtensionSupported(OES_EGL_sync);
+    }
+
+    if (WorkAroundDriverBugs() &&
+        Renderer() == GLRenderer::AndroidEmulator) {
+        // the Android emulator, which we use to run B2G reftests on,
+        // doesn't expose the OES_rgb8_rgba8 extension, but it seems to
+        // support it (tautologically, as it only runs on desktop GL).
+        MarkExtensionSupported(OES_rgb8_rgba8);
+    }
+
+    if (WorkAroundDriverBugs() &&
+        Vendor() == GLVendor::VMware &&
+        Renderer() == GLRenderer::GalliumLlvmpipe)
+    {
+        // The llvmpipe driver that is used on linux try servers appears to have
+        // buggy support for s3tc/dxt1 compressed textures.
+        // See Bug 975824.
+        MarkExtensionUnsupported(EXT_texture_compression_s3tc);
+        MarkExtensionUnsupported(EXT_texture_compression_dxt1);
+        MarkExtensionUnsupported(ANGLE_texture_compression_dxt3);
+        MarkExtensionUnsupported(ANGLE_texture_compression_dxt5);
+    }
+
+#ifdef DEBUG
+    firstRun = false;
+#endif
+}
+
+void
+GLContext::PlatformStartup()
+{
+  RegisterStrongMemoryReporter(new GfxTexturesReporter());
+}
+
+// Common code for checking for both GL extensions and GLX extensions.
+bool
+GLContext::ListHasExtension(const GLubyte *extensions, const char *extension)
+{
+    // fix bug 612572 - we were crashing as we were calling this function with extensions==null
+    if (extensions == nullptr || extension == nullptr)
+        return false;
+
+    const GLubyte *start;
+    GLubyte *where, *terminator;
+
+    /* Extension names should not have spaces. */
+    where = (GLubyte *) strchr(extension, ' ');
+    if (where || *extension == '\0')
+        return false;
+
+    /*
+     * It takes a bit of care to be fool-proof about parsing the
+     * OpenGL extensions string. Don't be fooled by sub-strings,
+     * etc.
+     */
+    start = extensions;
+    for (;;) {
+        where = (GLubyte *) strstr((const char *) start, extension);
+        if (!where) {
+            break;
+        }
+        terminator = where + strlen(extension);
+        if (where == start || *(where - 1) == ' ') {
+            if (*terminator == ' ' || *terminator == '\0') {
+                return true;
+            }
+        }
+        start = terminator;
+    }
+    return false;
+}
+
+void
+GLContext::DetermineCaps()
+{
+    PixelBufferFormat format = QueryPixelFormat();
+
+    SurfaceCaps caps;
+    caps.color = !!format.red && !!format.green && !!format.blue;
+    caps.bpp16 = caps.color && format.ColorBits() == 16;
+    caps.alpha = !!format.alpha;
+    caps.depth = !!format.depth;
+    caps.stencil = !!format.stencil;
+    caps.antialias = format.samples > 1;
+    caps.preserve = true;
+
+    mCaps = caps;
+}
+
+PixelBufferFormat
+GLContext::QueryPixelFormat()
+{
+    PixelBufferFormat format;
+
+    ScopedBindFramebuffer autoFB(this, 0);
+
+    fGetIntegerv(LOCAL_GL_RED_BITS  , &format.red  );
+    fGetIntegerv(LOCAL_GL_GREEN_BITS, &format.green);
+    fGetIntegerv(LOCAL_GL_BLUE_BITS , &format.blue );
+    fGetIntegerv(LOCAL_GL_ALPHA_BITS, &format.alpha);
+
+    fGetIntegerv(LOCAL_GL_DEPTH_BITS, &format.depth);
+    fGetIntegerv(LOCAL_GL_STENCIL_BITS, &format.stencil);
+
+    fGetIntegerv(LOCAL_GL_SAMPLES, &format.samples);
+
+    return format;
+}
+
+void
+GLContext::UpdatePixelFormat()
+{
+    PixelBufferFormat format = QueryPixelFormat();
+#ifdef DEBUG
+    const SurfaceCaps& caps = Caps();
+    MOZ_ASSERT(!caps.any, "Did you forget to DetermineCaps()?");
+
+    MOZ_ASSERT(caps.color == !!format.red);
+    MOZ_ASSERT(caps.color == !!format.green);
+    MOZ_ASSERT(caps.color == !!format.blue);
+
+    MOZ_ASSERT(caps.alpha == !!format.alpha);
+
+    // These we either must have if they're requested, or
+    // we can have if they're not.
+    MOZ_ASSERT(caps.depth == !!format.depth || !caps.depth);
+    MOZ_ASSERT(caps.stencil == !!format.stencil || !caps.stencil);
+
+    MOZ_ASSERT(caps.antialias == (format.samples > 1));
+#endif
+    mPixelFormat = new PixelBufferFormat(format);
+}
+
+GLFormats
+GLContext::ChooseGLFormats(const SurfaceCaps& caps) const
+{
+    GLFormats formats;
+
+    // If we're on ES2 hardware and we have an explicit request for 16 bits of color or less
+    // OR we don't support full 8-bit color, return a 4444 or 565 format.
+    bool bpp16 = caps.bpp16;
+    if (IsGLES()) {
+        if (!IsExtensionSupported(OES_rgb8_rgba8))
+            bpp16 = true;
+    } else {
+        // RGB565 is uncommon on desktop, requiring ARB_ES2_compatibility.
+        // Since it's also vanishingly useless there, let's not support it.
+        bpp16 = false;
+    }
+
+    if (bpp16) {
+        MOZ_ASSERT(IsGLES());
+        if (caps.alpha) {
+            formats.color_texInternalFormat = LOCAL_GL_RGBA;
+            formats.color_texFormat = LOCAL_GL_RGBA;
+            formats.color_texType   = LOCAL_GL_UNSIGNED_SHORT_4_4_4_4;
+            formats.color_rbFormat  = LOCAL_GL_RGBA4;
+        } else {
+            formats.color_texInternalFormat = LOCAL_GL_RGB;
+            formats.color_texFormat = LOCAL_GL_RGB;
+            formats.color_texType   = LOCAL_GL_UNSIGNED_SHORT_5_6_5;
+            formats.color_rbFormat  = LOCAL_GL_RGB565;
+        }
+    } else {
+        formats.color_texType = LOCAL_GL_UNSIGNED_BYTE;
+
+        if (caps.alpha) {
+            formats.color_texInternalFormat = IsGLES() ? LOCAL_GL_RGBA : LOCAL_GL_RGBA8;
+            formats.color_texFormat = LOCAL_GL_RGBA;
+            formats.color_rbFormat  = LOCAL_GL_RGBA8;
+        } else {
+            formats.color_texInternalFormat = IsGLES() ? LOCAL_GL_RGB : LOCAL_GL_RGB8;
+            formats.color_texFormat = LOCAL_GL_RGB;
+            formats.color_rbFormat  = LOCAL_GL_RGB8;
+        }
+    }
+
+    uint32_t msaaLevel = gfxPrefs::MSAALevel();
+    GLsizei samples = msaaLevel * msaaLevel;
+    samples = std::min(samples, mMaxSamples);
+
+    // Bug 778765.
+    if (WorkAroundDriverBugs() && samples == 1) {
+        samples = 0;
+    }
+    formats.samples = samples;
+
+
+    // Be clear that these are 0 if unavailable.
+    formats.depthStencil = 0;
+    if (!IsGLES() || IsExtensionSupported(OES_packed_depth_stencil)) {
+        formats.depthStencil = LOCAL_GL_DEPTH24_STENCIL8;
+    }
+
+    formats.depth = 0;
+    if (IsGLES()) {
+        if (IsExtensionSupported(OES_depth24)) {
+            formats.depth = LOCAL_GL_DEPTH_COMPONENT24;
+        } else {
+            formats.depth = LOCAL_GL_DEPTH_COMPONENT16;
+        }
+    } else {
+        formats.depth = LOCAL_GL_DEPTH_COMPONENT24;
+    }
+
+    formats.stencil = LOCAL_GL_STENCIL_INDEX8;
+
+    return formats;
+}
+
+bool
+GLContext::IsFramebufferComplete(GLuint fb, GLenum* pStatus)
+{
+    MOZ_ASSERT(fb);
+
+    ScopedBindFramebuffer autoFB(this, fb);
+    MOZ_ASSERT(fIsFramebuffer(fb));
+
+    GLenum status = fCheckFramebufferStatus(LOCAL_GL_FRAMEBUFFER);
+    if (pStatus)
+        *pStatus = status;
+
+    return status == LOCAL_GL_FRAMEBUFFER_COMPLETE;
+}
+
+void
+GLContext::AttachBuffersToFB(GLuint colorTex, GLuint colorRB,
+                             GLuint depthRB, GLuint stencilRB,
+                             GLuint fb, GLenum target)
+{
+    MOZ_ASSERT(fb);
+    MOZ_ASSERT( !(colorTex && colorRB) );
+
+    ScopedBindFramebuffer autoFB(this, fb);
+    MOZ_ASSERT(fIsFramebuffer(fb)); // It only counts after being bound.
+
+    if (colorTex) {
+        MOZ_ASSERT(fIsTexture(colorTex));
+        MOZ_ASSERT(target == LOCAL_GL_TEXTURE_2D ||
+                   target == LOCAL_GL_TEXTURE_RECTANGLE_ARB);
+        fFramebufferTexture2D(LOCAL_GL_FRAMEBUFFER,
+                              LOCAL_GL_COLOR_ATTACHMENT0,
+                              target,
+                              colorTex,
+                              0);
+    } else if (colorRB) {
+        MOZ_ASSERT(fIsRenderbuffer(colorRB));
+        fFramebufferRenderbuffer(LOCAL_GL_FRAMEBUFFER,
+                                 LOCAL_GL_COLOR_ATTACHMENT0,
+                                 LOCAL_GL_RENDERBUFFER,
+                                 colorRB);
+    }
+
+    if (depthRB) {
+        MOZ_ASSERT(fIsRenderbuffer(depthRB));
+        fFramebufferRenderbuffer(LOCAL_GL_FRAMEBUFFER,
+                                 LOCAL_GL_DEPTH_ATTACHMENT,
+                                 LOCAL_GL_RENDERBUFFER,
+                                 depthRB);
+    }
+
+    if (stencilRB) {
+        MOZ_ASSERT(fIsRenderbuffer(stencilRB));
+        fFramebufferRenderbuffer(LOCAL_GL_FRAMEBUFFER,
+                                 LOCAL_GL_STENCIL_ATTACHMENT,
+                                 LOCAL_GL_RENDERBUFFER,
+                                 stencilRB);
+    }
+}
+
+bool
+GLContext::AssembleOffscreenFBs(const GLuint colorMSRB,
+                                const GLuint depthRB,
+                                const GLuint stencilRB,
+                                const GLuint texture,
+                                GLuint* drawFB_out,
+                                GLuint* readFB_out)
+{
+    if (!colorMSRB && !texture) {
+        MOZ_ASSERT(!depthRB && !stencilRB);
+
+        if (drawFB_out)
+            *drawFB_out = 0;
+        if (readFB_out)
+            *readFB_out = 0;
+
+        return true;
+    }
+
+    ScopedBindFramebuffer autoFB(this);
+
+    GLuint drawFB = 0;
+    GLuint readFB = 0;
+
+    if (texture) {
+        readFB = 0;
+        fGenFramebuffers(1, &readFB);
+        BindFB(readFB);
+        fFramebufferTexture2D(LOCAL_GL_FRAMEBUFFER,
+                              LOCAL_GL_COLOR_ATTACHMENT0,
+                              LOCAL_GL_TEXTURE_2D,
+                              texture,
+                              0);
+    }
+
+    if (colorMSRB) {
+        drawFB = 0;
+        fGenFramebuffers(1, &drawFB);
+        BindFB(drawFB);
+        fFramebufferRenderbuffer(LOCAL_GL_FRAMEBUFFER,
+                                 LOCAL_GL_COLOR_ATTACHMENT0,
+                                 LOCAL_GL_RENDERBUFFER,
+                                 colorMSRB);
+    } else {
+        drawFB = readFB;
+    }
+    MOZ_ASSERT(GetFB() == drawFB);
+
+    if (depthRB) {
+        fFramebufferRenderbuffer(LOCAL_GL_FRAMEBUFFER,
+                                 LOCAL_GL_DEPTH_ATTACHMENT,
+                                 LOCAL_GL_RENDERBUFFER,
+                                 depthRB);
+    }
+
+    if (stencilRB) {
+        fFramebufferRenderbuffer(LOCAL_GL_FRAMEBUFFER,
+                                 LOCAL_GL_STENCIL_ATTACHMENT,
+                                 LOCAL_GL_RENDERBUFFER,
+                                 stencilRB);
+    }
+
+    // We should be all resized.  Check for framebuffer completeness.
+    GLenum status;
+    bool isComplete = true;
+
+    if (!IsFramebufferComplete(drawFB, &status)) {
+        NS_WARNING("DrawFBO: Incomplete");
+  #ifdef DEBUG
+        if (DebugMode()) {
+            printf_stderr("Framebuffer status: %X\n", status);
+        }
+  #endif
+        isComplete = false;
+    }
+
+    if (!IsFramebufferComplete(readFB, &status)) {
+        NS_WARNING("ReadFBO: Incomplete");
+  #ifdef DEBUG
+        if (DebugMode()) {
+            printf_stderr("Framebuffer status: %X\n", status);
+        }
+  #endif
+        isComplete = false;
+    }
+
+    if (drawFB_out) {
+        *drawFB_out = drawFB;
+    } else if (drawFB) {
+        NS_RUNTIMEABORT("drawFB created when not requested!");
+    }
+
+    if (readFB_out) {
+        *readFB_out = readFB;
+    } else if (readFB) {
+        NS_RUNTIMEABORT("readFB created when not requested!");
+    }
+
+    return isComplete;
+}
+
+
+
+bool
+GLContext::PublishFrame()
+{
+    MOZ_ASSERT(mScreen);
+
+    if (!mScreen->PublishFrame(OffscreenSize()))
+        return false;
+
+    return true;
+}
+
+SharedSurface_GL*
+GLContext::RequestFrame()
+{
+    MOZ_ASSERT(mScreen);
+
+    SharedSurface* ret = mScreen->Stream()->SwapConsumer();
+    if (!ret)
+        return nullptr;
+
+    return SharedSurface_GL::Cast(ret);
+}
+
+
+
+void
+GLContext::ClearSafely()
+{
+    // bug 659349 --- we must be very careful here: clearing a GL framebuffer is nontrivial, relies on a lot of state,
+    // and in the case of the backbuffer of a WebGL context, state is exposed to scripts.
+    //
+    // The code here is taken from WebGLContext::ForceClearFramebufferWithDefaultValues, but I didn't find a good way of
+    // sharing code with it. WebGL's code is somewhat performance-critical as it is typically called on every frame, so
+    // WebGL keeps track of GL state to avoid having to query it everytime, and also tries to only do work for actually
+    // present buffers (e.g. stencil buffer). Doing that here seems like premature optimization,
+    // as ClearSafely() is called only when e.g. a canvas is resized, not on every animation frame.
+
+    realGLboolean scissorTestEnabled;
+    realGLboolean ditherEnabled;
+    realGLboolean colorWriteMask[4];
+    realGLboolean depthWriteMask;
+    GLint stencilWriteMaskFront, stencilWriteMaskBack;
+    GLfloat colorClearValue[4];
+    GLfloat depthClearValue;
+    GLint stencilClearValue;
+
+    // save current GL state
+    fGetBooleanv(LOCAL_GL_SCISSOR_TEST, &scissorTestEnabled);
+    fGetBooleanv(LOCAL_GL_DITHER, &ditherEnabled);
+    fGetBooleanv(LOCAL_GL_COLOR_WRITEMASK, colorWriteMask);
+    fGetBooleanv(LOCAL_GL_DEPTH_WRITEMASK, &depthWriteMask);
+    fGetIntegerv(LOCAL_GL_STENCIL_WRITEMASK, &stencilWriteMaskFront);
+    fGetIntegerv(LOCAL_GL_STENCIL_BACK_WRITEMASK, &stencilWriteMaskBack);
+    fGetFloatv(LOCAL_GL_COLOR_CLEAR_VALUE, colorClearValue);
+    fGetFloatv(LOCAL_GL_DEPTH_CLEAR_VALUE, &depthClearValue);
+    fGetIntegerv(LOCAL_GL_STENCIL_CLEAR_VALUE, &stencilClearValue);
+
+    // prepare GL state for clearing
+    fDisable(LOCAL_GL_SCISSOR_TEST);
+    fDisable(LOCAL_GL_DITHER);
+
+    fColorMask(1, 1, 1, 1);
+    fClearColor(0.f, 0.f, 0.f, 0.f);
+
+    fDepthMask(1);
+    fClearDepth(1.0f);
+
+    fStencilMask(0xffffffff);
+    fClearStencil(0);
+
+    // do clear
+    fClear(LOCAL_GL_COLOR_BUFFER_BIT |
+           LOCAL_GL_DEPTH_BUFFER_BIT |
+           LOCAL_GL_STENCIL_BUFFER_BIT);
+
+    // restore GL state after clearing
+    fColorMask(colorWriteMask[0],
+               colorWriteMask[1],
+               colorWriteMask[2],
+               colorWriteMask[3]);
+    fClearColor(colorClearValue[0],
+                colorClearValue[1],
+                colorClearValue[2],
+                colorClearValue[3]);
+
+    fDepthMask(depthWriteMask);
+    fClearDepth(depthClearValue);
+
+    fStencilMaskSeparate(LOCAL_GL_FRONT, stencilWriteMaskFront);
+    fStencilMaskSeparate(LOCAL_GL_BACK, stencilWriteMaskBack);
+    fClearStencil(stencilClearValue);
+
+    if (ditherEnabled)
+        fEnable(LOCAL_GL_DITHER);
+    else
+        fDisable(LOCAL_GL_DITHER);
+
+    if (scissorTestEnabled)
+        fEnable(LOCAL_GL_SCISSOR_TEST);
+    else
+        fDisable(LOCAL_GL_SCISSOR_TEST);
+
+}
+
+void
+GLContext::MarkDestroyed()
+{
+    if (IsDestroyed())
+        return;
+
+    if (MakeCurrent()) {
+        DestroyScreenBuffer();
+
+        mBlitHelper = nullptr;
+        mBlitTextureImageHelper = nullptr;
+        mReadTexImageHelper = nullptr;
+
+        mTexGarbageBin->GLContextTeardown();
+    } else {
+        NS_WARNING("MakeCurrent() failed during MarkDestroyed! Skipping GL object teardown.");
+    }
+
+    mSymbols.Zero();
+}
+
+#ifdef MOZ_ENABLE_GL_TRACKING
+void
+GLContext::CreatedProgram(GLContext *aOrigin, GLuint aName)
+{
+    mTrackedPrograms.AppendElement(NamedResource(aOrigin, aName));
+}
+
+void
+GLContext::CreatedShader(GLContext *aOrigin, GLuint aName)
+{
+    mTrackedShaders.AppendElement(NamedResource(aOrigin, aName));
+}
+
+void
+GLContext::CreatedBuffers(GLContext *aOrigin, GLsizei aCount, GLuint *aNames)
+{
+    for (GLsizei i = 0; i < aCount; ++i) {
+        mTrackedBuffers.AppendElement(NamedResource(aOrigin, aNames[i]));
+    }
+}
+
+void
+GLContext::CreatedQueries(GLContext *aOrigin, GLsizei aCount, GLuint *aNames)
+{
+    for (GLsizei i = 0; i < aCount; ++i) {
+        mTrackedQueries.AppendElement(NamedResource(aOrigin, aNames[i]));
+    }
+}
+
+void
+GLContext::CreatedTextures(GLContext *aOrigin, GLsizei aCount, GLuint *aNames)
+{
+    for (GLsizei i = 0; i < aCount; ++i) {
+        mTrackedTextures.AppendElement(NamedResource(aOrigin, aNames[i]));
+    }
+}
+
+void
+GLContext::CreatedFramebuffers(GLContext *aOrigin, GLsizei aCount, GLuint *aNames)
+{
+    for (GLsizei i = 0; i < aCount; ++i) {
+        mTrackedFramebuffers.AppendElement(NamedResource(aOrigin, aNames[i]));
+    }
+}
+
+void
+GLContext::CreatedRenderbuffers(GLContext *aOrigin, GLsizei aCount, GLuint *aNames)
+{
+    for (GLsizei i = 0; i < aCount; ++i) {
+        mTrackedRenderbuffers.AppendElement(NamedResource(aOrigin, aNames[i]));
+    }
+}
+
+static void
+RemoveNamesFromArray(GLContext *aOrigin, GLsizei aCount, const GLuint *aNames, nsTArray<GLContext::NamedResource>& aArray)
+{
+    for (GLsizei j = 0; j < aCount; ++j) {
+        GLuint name = aNames[j];
+        // name 0 can be ignored
+        if (name == 0)
+            continue;
+
+        for (uint32_t i = 0; i < aArray.Length(); ++i) {
+            if (aArray[i].name == name) {
+                aArray.RemoveElementAt(i);
+                break;
+            }
+        }
+    }
+}
+
+void
+GLContext::DeletedProgram(GLContext *aOrigin, GLuint aName)
+{
+    RemoveNamesFromArray(aOrigin, 1, &aName, mTrackedPrograms);
+}
+
+void
+GLContext::DeletedShader(GLContext *aOrigin, GLuint aName)
+{
+    RemoveNamesFromArray(aOrigin, 1, &aName, mTrackedShaders);
+}
+
+void
+GLContext::DeletedBuffers(GLContext *aOrigin, GLsizei aCount, const GLuint *aNames)
+{
+    RemoveNamesFromArray(aOrigin, aCount, aNames, mTrackedBuffers);
+}
+
+void
+GLContext::DeletedQueries(GLContext *aOrigin, GLsizei aCount, const GLuint *aNames)
+{
+    RemoveNamesFromArray(aOrigin, aCount, aNames, mTrackedQueries);
+}
+
+void
+GLContext::DeletedTextures(GLContext *aOrigin, GLsizei aCount, const GLuint *aNames)
+{
+    RemoveNamesFromArray(aOrigin, aCount, aNames, mTrackedTextures);
+}
+
+void
+GLContext::DeletedFramebuffers(GLContext *aOrigin, GLsizei aCount, const GLuint *aNames)
+{
+    RemoveNamesFromArray(aOrigin, aCount, aNames, mTrackedFramebuffers);
+}
+
+void
+GLContext::DeletedRenderbuffers(GLContext *aOrigin, GLsizei aCount, const GLuint *aNames)
+{
+    RemoveNamesFromArray(aOrigin, aCount, aNames, mTrackedRenderbuffers);
+}
+
+static void
+MarkContextDestroyedInArray(GLContext *aContext, nsTArray<GLContext::NamedResource>& aArray)
+{
+    for (uint32_t i = 0; i < aArray.Length(); ++i) {
+        if (aArray[i].origin == aContext)
+            aArray[i].originDeleted = true;
+    }
+}
+
+void
+GLContext::SharedContextDestroyed(GLContext *aChild)
+{
+    MarkContextDestroyedInArray(aChild, mTrackedPrograms);
+    MarkContextDestroyedInArray(aChild, mTrackedShaders);
+    MarkContextDestroyedInArray(aChild, mTrackedTextures);
+    MarkContextDestroyedInArray(aChild, mTrackedFramebuffers);
+    MarkContextDestroyedInArray(aChild, mTrackedRenderbuffers);
+    MarkContextDestroyedInArray(aChild, mTrackedBuffers);
+    MarkContextDestroyedInArray(aChild, mTrackedQueries);
+}
+
+static void
+ReportArrayContents(const char *title, const nsTArray<GLContext::NamedResource>& aArray)
+{
+    if (aArray.Length() == 0)
+        return;
+
+    printf_stderr("%s:\n", title);
+
+    nsTArray<GLContext::NamedResource> copy(aArray);
+    copy.Sort();
+
+    GLContext *lastContext = nullptr;
+    for (uint32_t i = 0; i < copy.Length(); ++i) {
+        if (lastContext != copy[i].origin) {
+            if (lastContext)
+                printf_stderr("\n");
+            printf_stderr("  [%p - %s] ", copy[i].origin, copy[i].originDeleted ? "deleted" : "live");
+            lastContext = copy[i].origin;
+        }
+        printf_stderr("%d ", copy[i].name);
+    }
+    printf_stderr("\n");
+}
+
+void
+GLContext::ReportOutstandingNames()
+{
+    if (!DebugMode())
+        return;
+
+    printf_stderr("== GLContext %p Outstanding ==\n", this);
+
+    ReportArrayContents("Outstanding Textures", mTrackedTextures);
+    ReportArrayContents("Outstanding Buffers", mTrackedBuffers);
+    ReportArrayContents("Outstanding Queries", mTrackedQueries);
+    ReportArrayContents("Outstanding Programs", mTrackedPrograms);
+    ReportArrayContents("Outstanding Shaders", mTrackedShaders);
+    ReportArrayContents("Outstanding Framebuffers", mTrackedFramebuffers);
+    ReportArrayContents("Outstanding Renderbuffers", mTrackedRenderbuffers);
+}
+
+#endif /* DEBUG */
+
+
+void
+GLContext::GuaranteeResolve()
+{
+    if (mScreen) {
+        mScreen->AssureBlitted();
+    }
+    fFinish();
+}
+
+const gfx::IntSize&
+GLContext::OffscreenSize() const
+{
+    MOZ_ASSERT(IsOffscreen());
+    return mScreen->Size();
+}
+
+bool
+GLContext::CreateScreenBufferImpl(const IntSize& size, const SurfaceCaps& caps)
+{
+    GLScreenBuffer* newScreen = GLScreenBuffer::Create(this, size, caps);
+    if (!newScreen)
+        return false;
+
+    if (!newScreen->Resize(size)) {
+        delete newScreen;
+        return false;
+    }
+
+    DestroyScreenBuffer();
+
+    // This will rebind to 0 (Screen) if needed when
+    // it falls out of scope.
+    ScopedBindFramebuffer autoFB(this);
+
+    mScreen = newScreen;
+
+    return true;
+}
+
+bool
+GLContext::ResizeScreenBuffer(const IntSize& size)
+{
+    if (!IsOffscreenSizeAllowed(size))
+        return false;
+
+    return mScreen->Resize(size);
+}
+
+
+void
+GLContext::DestroyScreenBuffer()
+{
+    delete mScreen;
+    mScreen = nullptr;
+}
+
+void
+GLContext::ForceDirtyScreen()
+{
+    ScopedBindFramebuffer autoFB(0);
+
+    BeforeGLDrawCall();
+    // no-op; just pretend we did something
+    AfterGLDrawCall();
+}
+
+void
+GLContext::CleanDirtyScreen()
+{
+    ScopedBindFramebuffer autoFB(0);
+
+    BeforeGLReadCall();
+    // no-op; we just want to make sure the Read FBO is updated if it needs to be
+    AfterGLReadCall();
+}
+
+void
+GLContext::EmptyTexGarbageBin()
+{
+   TexGarbageBin()->EmptyGarbage();
+}
+
+bool
+GLContext::IsOffscreenSizeAllowed(const IntSize& aSize) const {
+  int32_t biggerDimension = std::max(aSize.width, aSize.height);
+  int32_t maxAllowed = std::min(mMaxRenderbufferSize, mMaxTextureSize);
+  return biggerDimension <= maxAllowed;
+}
+
+bool
+GLContext::IsOwningThreadCurrent()
+{
+  return NS_GetCurrentThread() == mOwningThread;
+}
+
+void
+GLContext::DispatchToOwningThread(nsIRunnable *event)
+{
+    // Before dispatching, we need to ensure we're not in the middle of
+    // shutting down. Dispatching runnables in the middle of shutdown
+    // (that is, when the main thread is no longer get-able) can cause them
+    // to leak. See Bug 741319, and Bug 744115.
+    nsCOMPtr<nsIThread> mainThread;
+    if (NS_SUCCEEDED(NS_GetMainThread(getter_AddRefs(mainThread)))) {
+        mOwningThread->Dispatch(event, NS_DISPATCH_NORMAL);
+    }
+}
+
+GLBlitHelper*
+GLContext::BlitHelper()
+{
+    if (!mBlitHelper) {
+        mBlitHelper = new GLBlitHelper(this);
+    }
+
+    return mBlitHelper;
+}
+
+GLBlitTextureImageHelper*
+GLContext::BlitTextureImageHelper()
+{
+    if (!mBlitTextureImageHelper) {
+        mBlitTextureImageHelper = new GLBlitTextureImageHelper(this);
+    }
+
+    return mBlitTextureImageHelper;
+}
+
+GLReadTexImageHelper*
+GLContext::ReadTexImageHelper()
+{
+    if (!mReadTexImageHelper) {
+        mReadTexImageHelper = new GLReadTexImageHelper(this);
+    }
+
+    return mReadTexImageHelper;
+}
+
+bool
+DoesStringMatch(const char* aString, const char *aWantedString)
+{
+    if (!aString || !aWantedString)
+        return false;
+
+    const char *occurrence = strstr(aString, aWantedString);
+
+    // aWanted not found
+    if (!occurrence)
+        return false;
+
+    // aWantedString preceded by alpha character
+    if (occurrence != aString && isalpha(*(occurrence-1)))
+        return false;
+
+    // aWantedVendor followed by alpha character
+    const char *afterOccurrence = occurrence + strlen(aWantedString);
+    if (isalpha(*afterOccurrence))
+        return false;
+
+    return true;
+}
+
+} /* namespace gl */
+} /* namespace mozilla */