diff -r 000000000000 -r 6474c204b198 gfx/gl/SharedSurfaceIO.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/gl/SharedSurfaceIO.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,150 @@
+/* -*- Mode: c++; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40; -*- */
+/* 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 "SharedSurfaceIO.h"
+#include "GLContextCGL.h"
+#include "mozilla/gfx/MacIOSurface.h"
+#include "mozilla/DebugOnly.h"
+#include "ScopedGLHelpers.h"
+
+namespace mozilla {
+namespace gl {
+
+using namespace gfx;
+
+/* static */ SharedSurface_IOSurface*
+SharedSurface_IOSurface::Create(MacIOSurface* surface, GLContext *gl, bool hasAlpha)
+{
+    MOZ_ASSERT(surface);
+    MOZ_ASSERT(gl);
+
+    gfx::IntSize size(surface->GetWidth(), surface->GetHeight());
+    return new SharedSurface_IOSurface(surface, gl, size, hasAlpha);
+}
+
+void
+SharedSurface_IOSurface::Fence()
+{
+    mGL->MakeCurrent();
+    mGL->fFlush();
+}
+
+bool
+SharedSurface_IOSurface::ReadPixels(GLint x, GLint y, GLsizei width, GLsizei height,
+                                    GLenum format, GLenum type, GLvoid *pixels)
+{
+    // Calling glReadPixels when an IOSurface is bound to the current framebuffer
+    // can cause corruption in following glReadPixel calls (even if they aren't
+    // reading from an IOSurface).
+    // We workaround this by copying to a temporary texture, and doing the readback
+    // from that.
+    MOZ_ASSERT(mGL->IsCurrent());
+
+
+    ScopedTexture destTex(mGL);
+    {
+        ScopedFramebufferForTexture srcFB(mGL, ProdTexture(), ProdTextureTarget());
+
+        ScopedBindFramebuffer bindFB(mGL, srcFB.FB());
+        ScopedBindTexture bindTex(mGL, destTex.Texture());
+        mGL->fCopyTexImage2D(LOCAL_GL_TEXTURE_2D, 0,
+                             HasAlpha() ? LOCAL_GL_RGBA : LOCAL_GL_RGB,
+                             x, y,
+                             width, height, 0);
+    }
+
+    ScopedFramebufferForTexture destFB(mGL, destTex.Texture());
+
+    ScopedBindFramebuffer bindFB(mGL, destFB.FB());
+    mGL->fReadPixels(0, 0, width, height, format, type, pixels);
+    return true;
+}
+
+static void
+BackTextureWithIOSurf(GLContext* gl, GLuint tex, MacIOSurface* ioSurf)
+{
+    MOZ_ASSERT(gl->IsCurrent());
+
+    ScopedBindTexture texture(gl, tex, LOCAL_GL_TEXTURE_RECTANGLE_ARB);
+
+    gl->fTexParameteri(LOCAL_GL_TEXTURE_RECTANGLE_ARB,
+                        LOCAL_GL_TEXTURE_MIN_FILTER,
+                        LOCAL_GL_LINEAR);
+    gl->fTexParameteri(LOCAL_GL_TEXTURE_RECTANGLE_ARB,
+                        LOCAL_GL_TEXTURE_MAG_FILTER,
+                        LOCAL_GL_LINEAR);
+    gl->fTexParameteri(LOCAL_GL_TEXTURE_RECTANGLE_ARB,
+                        LOCAL_GL_TEXTURE_WRAP_S,
+                        LOCAL_GL_CLAMP_TO_EDGE);
+    gl->fTexParameteri(LOCAL_GL_TEXTURE_RECTANGLE_ARB,
+                        LOCAL_GL_TEXTURE_WRAP_T,
+                        LOCAL_GL_CLAMP_TO_EDGE);
+
+    CGLContextObj cgl = GLContextCGL::Cast(gl)->GetCGLContext();
+    MOZ_ASSERT(cgl);
+
+    ioSurf->CGLTexImageIOSurface2D(cgl);
+}
+
+SharedSurface_IOSurface::SharedSurface_IOSurface(MacIOSurface* surface,
+                                                 GLContext* gl,
+                                                 const gfx::IntSize& size,
+                                                 bool hasAlpha)
+  : SharedSurface_GL(SharedSurfaceType::IOSurface, AttachmentType::GLTexture, gl, size, hasAlpha)
+  , mSurface(surface)
+  , mCurConsGL(nullptr)
+  , mConsTex(0)
+{
+    gl->MakeCurrent();
+    mProdTex = 0;
+    gl->fGenTextures(1, &mProdTex);
+    BackTextureWithIOSurf(gl, mProdTex, surface);
+}
+
+GLuint
+SharedSurface_IOSurface::ConsTexture(GLContext* consGL)
+{
+    if (!mCurConsGL) {
+        mCurConsGL = consGL;
+    }
+    MOZ_ASSERT(consGL == mCurConsGL);
+
+    if (!mConsTex) {
+        consGL->MakeCurrent();
+        mConsTex = 0;
+        consGL->fGenTextures(1, &mConsTex);
+        BackTextureWithIOSurf(consGL, mConsTex, mSurface);
+    }
+
+    return mConsTex;
+}
+
+SharedSurface_IOSurface::~SharedSurface_IOSurface()
+{
+    if (mProdTex) {
+        DebugOnly<bool> success = mGL->MakeCurrent();
+        MOZ_ASSERT(success);
+        mGL->fDeleteTextures(1, &mProdTex);
+        mGL->fDeleteTextures(1, &mConsTex); // This will work if we're shared.
+    }
+}
+
+SharedSurface*
+SurfaceFactory_IOSurface::CreateShared(const gfx::IntSize& size)
+{
+    bool hasAlpha = mReadCaps.alpha;
+    RefPtr<MacIOSurface> surf =
+        MacIOSurface::CreateIOSurface(size.width, size.height, 1.0, hasAlpha);
+
+    if (!surf) {
+        NS_WARNING("Failed to create MacIOSurface.");
+        return nullptr;
+    }
+
+    return SharedSurface_IOSurface::Create(surf, mGL, hasAlpha);
+}
+
+}
+}