diff -r 000000000000 -r 6474c204b198 content/canvas/src/WebGL2Context.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/canvas/src/WebGL2Context.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,129 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "WebGL2Context.h"
+#include "GLContext.h"
+#include "mozilla/dom/WebGL2RenderingContextBinding.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Telemetry.h"
+
+using namespace mozilla;
+using namespace mozilla::gl;
+
+// -----------------------------------------------------------------------------
+// CONSTRUCTOR & DESTRUCTOR
+
+WebGL2Context::WebGL2Context()
+    : WebGLContext()
+{
+    MOZ_ASSERT(IsSupported(), "not supposed to create a WebGL2Context"
+                              "context when not supported");
+}
+
+WebGL2Context::~WebGL2Context()
+{
+
+}
+
+
+// -----------------------------------------------------------------------------
+// STATIC FUNCTIONS
+
+bool
+WebGL2Context::IsSupported()
+{
+    return Preferences::GetBool("webgl.enable-prototype-webgl2", false);
+}
+
+WebGL2Context*
+WebGL2Context::Create()
+{
+    return new WebGL2Context();
+}
+
+
+// -----------------------------------------------------------------------------
+// IMPLEMENT nsWrapperCache
+
+JSObject*
+WebGL2Context::WrapObject(JSContext *cx)
+{
+    return dom::WebGL2RenderingContextBinding::Wrap(cx, this);
+}
+
+
+// -----------------------------------------------------------------------------
+// WebGL 2 initialisation
+
+bool
+WebGLContext::InitWebGL2()
+{
+    MOZ_ASSERT(IsWebGL2(), "WebGLContext is not a WebGL 2 context!");
+
+    const WebGLExtensionID sExtensionNativelySupportedArr[] = {
+        WebGLExtensionID::ANGLE_instanced_arrays,
+        WebGLExtensionID::OES_element_index_uint,
+        WebGLExtensionID::OES_standard_derivatives,
+        WebGLExtensionID::OES_texture_float,
+        WebGLExtensionID::OES_texture_float_linear,
+        WebGLExtensionID::OES_vertex_array_object,
+        WebGLExtensionID::WEBGL_depth_texture,
+        WebGLExtensionID::WEBGL_draw_buffers
+    };
+    const GLFeature sFeatureRequiredArr[] = {
+        GLFeature::blend_minmax,
+        GLFeature::instanced_non_arrays,
+        GLFeature::transform_feedback
+    };
+
+    // check WebGL extensions that are supposed to be natively supported
+    for (size_t i = 0; i < size_t(MOZ_ARRAY_LENGTH(sExtensionNativelySupportedArr)); i++)
+    {
+        WebGLExtensionID extension = sExtensionNativelySupportedArr[i];
+
+        if (!IsExtensionSupported(extension)) {
+            GenerateWarning("WebGL 2 requires %s!", GetExtensionString(extension));
+            return false;
+        }
+    }
+
+    // check required OpenGL extensions
+    if (!gl->IsExtensionSupported(GLContext::EXT_gpu_shader4)) {
+        GenerateWarning("WebGL 2 requires GL_EXT_gpu_shader4!");
+        return false;
+    }
+
+    // check OpenGL features
+    if (!gl->IsSupported(GLFeature::occlusion_query) &&
+        !gl->IsSupported(GLFeature::occlusion_query_boolean))
+    {
+        /*
+         * on desktop, we fake occlusion_query_boolean with occlusion_query if
+         * necessary. See WebGLContextAsyncQueries.cpp.
+         */
+        GenerateWarning("WebGL 2 requires occlusion queries!");
+        return false;
+    }
+
+    for (size_t i = 0; i < size_t(MOZ_ARRAY_LENGTH(sFeatureRequiredArr)); i++)
+    {
+        if (!gl->IsSupported(sFeatureRequiredArr[i])) {
+            GenerateWarning("WebGL 2 requires GLFeature::%s!", GLContext::GetFeatureName(sFeatureRequiredArr[i]));
+            return false;
+        }
+    }
+
+    // ok WebGL 2 is compatible, we can enable natively supported extensions.
+    for (size_t i = 0; i < size_t(MOZ_ARRAY_LENGTH(sExtensionNativelySupportedArr)); i++) {
+        EnableExtension(sExtensionNativelySupportedArr[i]);
+
+        MOZ_ASSERT(IsExtensionEnabled(sExtensionNativelySupportedArr[i]));
+    }
+
+    // we initialise WebGL 2 related stuff.
+    gl->GetUIntegerv(LOCAL_GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS, &mGLMaxTransformFeedbackSeparateAttribs);
+
+    return true;
+}