--- a/content/canvas/src/WebGLContext.h
+++ b/content/canvas/src/WebGLContext.h
@@ -4,16 +4,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef WEBGLCONTEXT_H_
 #define WEBGLCONTEXT_H_
 
 #include "WebGLElementArrayCache.h"
 #include "WebGLObjectModel.h"
 #include "WebGLBuffer.h"
+#include "WebGLRenderbuffer.h"
 #include "WebGLVertexAttribData.h"
 #include "WebGLShaderPrecisionFormat.h"
 #include <stdarg.h>
 #include <vector>
 
 #include "nsTArray.h"
 #include "nsDataHashtable.h"
 #include "nsHashKeys.h"
@@ -69,19 +70,17 @@ class nsIPropertyBag;
 
 namespace mozilla {
 
 class WebGLTexture;
 class WebGLProgram;
 class WebGLShader;
 class WebGLFramebuffer;
 class WebGLUniformLocation;
-class WebGLRenderbuffer;
 class WebGLMemoryPressureObserver;
-class WebGLRectangleObject;
 class WebGLContextBoundObject;
 class WebGLActiveInfo;
 class WebGLExtensionBase;
 
 namespace dom {
 struct WebGLContextAttributes;
 struct WebGLContextAttributesInitializer;
 }
@@ -146,57 +145,16 @@ using WebGLTexelConversions::WebGLTexelF
 WebGLTexelFormat GetWebGLTexelFormat(GLenum format, GLenum type);
 
 // Zero is not an integer power of two.
 inline bool is_pot_assuming_nonnegative(WebGLsizei x)
 {
     return x && (x & (x-1)) == 0;
 }
 
-// this class is a mixin for GL objects that have dimensions
-// that we need to track.
-class WebGLRectangleObject
-{
-public:
-    WebGLRectangleObject()
-        : mWidth(0), mHeight(0) { }
-
-    WebGLRectangleObject(WebGLsizei width, WebGLsizei height)
-        : mWidth(width), mHeight(height) { }
-
-    WebGLsizei Width() const { return mWidth; }
-    void width(WebGLsizei value) { mWidth = value; }
-
-    WebGLsizei Height() const { return mHeight; }
-    void height(WebGLsizei value) { mHeight = value; }
-
-    void setDimensions(WebGLsizei width, WebGLsizei height) {
-        mWidth = width;
-        mHeight = height;
-    }
-
-    void setDimensions(WebGLRectangleObject *rect) {
-        if (rect) {
-            mWidth = rect->Width();
-            mHeight = rect->Height();
-        } else {
-            mWidth = 0;
-            mHeight = 0;
-        }
-    }
-
-    bool HasSameDimensionsAs(const WebGLRectangleObject& other) const {
-        return Width() == other.Width() && Height() == other.Height(); 
-    }
-
-protected:
-    WebGLsizei mWidth;
-    WebGLsizei mHeight;
-};
-
 struct WebGLContextOptions {
     // these are defaults
     WebGLContextOptions();
 
     bool operator==(const WebGLContextOptions& other) const {
         return
             alpha == other.alpha &&
             depth == other.depth &&
@@ -2137,109 +2095,16 @@ protected:
 
     // post-link data
     std::vector<bool> mAttribsInUse;
     nsAutoPtr<CStringMap> mIdentifierMap, mIdentifierReverseMap;
     nsAutoPtr<CStringToUniformInfoMap> mUniformInfoMap;
     int mAttribMaxNameLength;
 };
 
-class WebGLRenderbuffer MOZ_FINAL
-    : public nsISupports
-    , public WebGLRefCountedObject<WebGLRenderbuffer>
-    , public LinkedListElement<WebGLRenderbuffer>
-    , public WebGLRectangleObject
-    , public WebGLContextBoundObject
-    , public nsWrapperCache
-{
-public:
-    WebGLRenderbuffer(WebGLContext *context)
-        : WebGLContextBoundObject(context)
-        , mInternalFormat(0)
-        , mInternalFormatForGL(0)
-        , mHasEverBeenBound(false)
-        , mInitialized(false)
-    {
-        SetIsDOMBinding();
-        mContext->MakeContextCurrent();
-        mContext->gl->fGenRenderbuffers(1, &mGLName);
-        mContext->mRenderbuffers.insertBack(this);
-    }
-
-    ~WebGLRenderbuffer() {
-        DeleteOnce();
-    }
-
-    void Delete() {
-        mContext->MakeContextCurrent();
-        mContext->gl->fDeleteRenderbuffers(1, &mGLName);
-        LinkedListElement<WebGLRenderbuffer>::removeFrom(mContext->mRenderbuffers);
-    }
-
-    bool HasEverBeenBound() { return mHasEverBeenBound; }
-    void SetHasEverBeenBound(bool x) { mHasEverBeenBound = x; }
-    WebGLuint GLName() const { return mGLName; }
-
-    bool Initialized() const { return mInitialized; }
-    void SetInitialized(bool aInitialized) { mInitialized = aInitialized; }
-
-    WebGLenum InternalFormat() const { return mInternalFormat; }
-    void SetInternalFormat(WebGLenum aInternalFormat) { mInternalFormat = aInternalFormat; }
-    
-    WebGLenum InternalFormatForGL() const { return mInternalFormatForGL; }
-    void SetInternalFormatForGL(WebGLenum aInternalFormatForGL) { mInternalFormatForGL = aInternalFormatForGL; }
-    
-    int64_t MemoryUsage() const {
-        int64_t pixels = int64_t(Width()) * int64_t(Height());
-
-        // If there is no defined format, we're not taking up any memory
-        if (!mInternalFormatForGL) {
-            return 0;
-        }
-
-        switch (mInternalFormatForGL) {
-            case LOCAL_GL_STENCIL_INDEX8:
-                return pixels;
-            case LOCAL_GL_RGBA4:
-            case LOCAL_GL_RGB5_A1:
-            case LOCAL_GL_RGB565:
-            case LOCAL_GL_DEPTH_COMPONENT16:
-                return 2 * pixels;
-            case LOCAL_GL_RGB8:
-            case LOCAL_GL_DEPTH_COMPONENT24:
-                return 3*pixels;
-            case LOCAL_GL_RGBA8:
-            case LOCAL_GL_DEPTH24_STENCIL8:
-                return 4*pixels;
-            default:
-                break;
-        }
-        NS_ABORT();
-        return 0;
-    }
-
-    WebGLContext *GetParentObject() const {
-        return Context();
-    }
-
-    virtual JSObject* WrapObject(JSContext *cx, JSObject *scope, bool *triedToWrap);
-
-    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-    NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(WebGLRenderbuffer)
-
-protected:
-
-    WebGLuint mGLName;
-    WebGLenum mInternalFormat;
-    WebGLenum mInternalFormatForGL;
-    bool mHasEverBeenBound;
-    bool mInitialized;
-
-    friend class WebGLFramebuffer;
-};
 
 class WebGLFramebufferAttachment
 {
     // deleting a texture or renderbuffer immediately detaches it
     WebGLRefPtr<WebGLTexture> mTexturePtr;
     WebGLRefPtr<WebGLRenderbuffer> mRenderbufferPtr;
     WebGLenum mAttachmentPoint;
     WebGLint mTextureLevel;

--- a/content/canvas/src/WebGLObjectModel.h
+++ b/content/canvas/src/WebGLObjectModel.h
@@ -278,16 +278,57 @@ public:
 
     WebGLContext *Context() const { return mContext; }
 
 protected:
     WebGLContext *mContext;
     uint32_t mContextGeneration;
 };
 
+// this class is a mixin for GL objects that have dimensions
+// that we need to track.
+class WebGLRectangleObject
+{
+public:
+    WebGLRectangleObject()
+        : mWidth(0), mHeight(0) { }
+
+    WebGLRectangleObject(WebGLsizei width, WebGLsizei height)
+        : mWidth(width), mHeight(height) { }
+
+    WebGLsizei Width() const { return mWidth; }
+    void width(WebGLsizei value) { mWidth = value; }
+
+    WebGLsizei Height() const { return mHeight; }
+    void height(WebGLsizei value) { mHeight = value; }
+
+    void setDimensions(WebGLsizei width, WebGLsizei height) {
+        mWidth = width;
+        mHeight = height;
+    }
+
+    void setDimensions(WebGLRectangleObject *rect) {
+        if (rect) {
+            mWidth = rect->Width();
+            mHeight = rect->Height();
+        } else {
+            mWidth = 0;
+            mHeight = 0;
+        }
+    }
+
+    bool HasSameDimensionsAs(const WebGLRectangleObject& other) const {
+        return Width() == other.Width() && Height() == other.Height(); 
+    }
+
+protected:
+    WebGLsizei mWidth;
+    WebGLsizei mHeight;
+};
+
 }// namespace mozilla
 
 template <typename T>
 inline void
 ImplCycleCollectionUnlink(mozilla::WebGLRefPtr<T>& aField)
 {
   aField = nullptr;
 }

--- a/content/canvas/src/WebGLRenderbuffer.cpp
+++ b/content/canvas/src/WebGLRenderbuffer.cpp
@@ -1,23 +1,74 @@
 /* -*- 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 "WebGLContext.h"
+#include "WebGLRenderbuffer.h"
 #include "mozilla/dom/WebGLRenderingContextBinding.h"
 
 using namespace mozilla;
 
 JSObject*
 WebGLRenderbuffer::WrapObject(JSContext *cx, JSObject *scope, bool *triedToWrap) {
     return dom::WebGLRenderbufferBinding::Wrap(cx, scope, this, triedToWrap);
 }
 
+WebGLRenderbuffer::WebGLRenderbuffer(WebGLContext *context)
+    : WebGLContextBoundObject(context)
+    , mInternalFormat(0)
+    , mInternalFormatForGL(0)
+    , mHasEverBeenBound(false)
+    , mInitialized(false)
+{
+    SetIsDOMBinding();
+    mContext->MakeContextCurrent();
+    mContext->gl->fGenRenderbuffers(1, &mGLName);
+    mContext->mRenderbuffers.insertBack(this);
+}
+
+void
+WebGLRenderbuffer::Delete() {
+    mContext->MakeContextCurrent();
+    mContext->gl->fDeleteRenderbuffers(1, &mGLName);
+    LinkedListElement<WebGLRenderbuffer>::removeFrom(mContext->mRenderbuffers);
+}
+
+int64_t
+WebGLRenderbuffer::MemoryUsage() const {
+    int64_t pixels = int64_t(Width()) * int64_t(Height());
+
+    // If there is no defined format, we're not taking up any memory
+    if (!mInternalFormatForGL) {
+        return 0;
+    }
+
+    switch (mInternalFormatForGL) {
+        case LOCAL_GL_STENCIL_INDEX8:
+            return pixels;
+        case LOCAL_GL_RGBA4:
+        case LOCAL_GL_RGB5_A1:
+        case LOCAL_GL_RGB565:
+        case LOCAL_GL_DEPTH_COMPONENT16:
+            return 2 * pixels;
+        case LOCAL_GL_RGB8:
+        case LOCAL_GL_DEPTH_COMPONENT24:
+            return 3*pixels;
+        case LOCAL_GL_RGBA8:
+        case LOCAL_GL_DEPTH24_STENCIL8:
+            return 4*pixels;
+        default:
+            break;
+    }
+    NS_ABORT();
+    return 0;
+}
+
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(WebGLRenderbuffer)
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(WebGLRenderbuffer)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(WebGLRenderbuffer)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(WebGLRenderbuffer)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRY(nsISupports)

new file mode 100644
--- /dev/null
+++ b/content/canvas/src/WebGLRenderbuffer.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 4; 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/. */
+
+#ifndef WEBGLRENDERBUFFER_H_
+#define WEBGLRENDERBUFFER_H_
+
+#include "WebGLObjectModel.h"
+
+#include "nsWrapperCache.h"
+
+#include "mozilla/LinkedList.h"
+
+namespace mozilla {
+
+class WebGLRenderbuffer MOZ_FINAL
+    : public nsISupports
+    , public WebGLRefCountedObject<WebGLRenderbuffer>
+    , public LinkedListElement<WebGLRenderbuffer>
+    , public WebGLRectangleObject
+    , public WebGLContextBoundObject
+    , public nsWrapperCache
+{
+public:
+    WebGLRenderbuffer(WebGLContext *context);
+
+    ~WebGLRenderbuffer() {
+        DeleteOnce();
+    }
+
+    void Delete();
+
+    bool HasEverBeenBound() { return mHasEverBeenBound; }
+    void SetHasEverBeenBound(bool x) { mHasEverBeenBound = x; }
+    WebGLuint GLName() const { return mGLName; }
+
+    bool Initialized() const { return mInitialized; }
+    void SetInitialized(bool aInitialized) { mInitialized = aInitialized; }
+
+    WebGLenum InternalFormat() const { return mInternalFormat; }
+    void SetInternalFormat(WebGLenum aInternalFormat) { mInternalFormat = aInternalFormat; }
+
+    WebGLenum InternalFormatForGL() const { return mInternalFormatForGL; }
+    void SetInternalFormatForGL(WebGLenum aInternalFormatForGL) { mInternalFormatForGL = aInternalFormatForGL; }
+
+    int64_t MemoryUsage() const;
+
+    WebGLContext *GetParentObject() const {
+        return Context();
+    }
+
+    virtual JSObject* WrapObject(JSContext *cx, JSObject *scope, bool *triedToWrap);
+
+    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+    NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(WebGLRenderbuffer)
+
+protected:
+
+    WebGLuint mGLName;
+    WebGLenum mInternalFormat;
+    WebGLenum mInternalFormatForGL;
+    bool mHasEverBeenBound;
+    bool mInitialized;
+
+    friend class WebGLFramebuffer;
+};
+} // namespace mozilla
+
+#endif