diff -r 000000000000 -r 6474c204b198 content/canvas/src/WebGLFramebufferAttachable.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/canvas/src/WebGLFramebufferAttachable.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,64 @@
+/* -*- 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 "WebGLFramebufferAttachable.h"
+#include "WebGLFramebuffer.h"
+#include "WebGLRenderbuffer.h"
+#include "WebGLTexture.h"
+
+using namespace mozilla;
+
+WebGLFramebufferAttachable::AttachmentPoint*
+WebGLFramebufferAttachable::Contains(const WebGLFramebuffer* fb, GLenum attachment)
+{
+    AttachmentPoint* first = mAttachmentPoints.begin();
+    AttachmentPoint* last = mAttachmentPoints.end();
+
+    for (; first != last; ++first) {
+        if (first->mFB == fb && first->mAttachment == attachment)
+            return first;
+    }
+
+    return nullptr;
+}
+
+void
+WebGLFramebufferAttachable::AttachTo(WebGLFramebuffer* fb, GLenum attachment)
+{
+    MOZ_ASSERT(fb);
+    if (!fb)
+        return;
+
+    if (Contains(fb, attachment))
+        return; // Already attached. Ignore.
+
+    mAttachmentPoints.append(AttachmentPoint(fb, attachment));
+}
+
+void
+WebGLFramebufferAttachable::DetachFrom(WebGLFramebuffer* fb, GLenum attachment)
+{
+    MOZ_ASSERT(fb);
+    if (!fb)
+        return;
+
+    AttachmentPoint* point = Contains(fb, attachment);
+    if (!point) {
+        MOZ_ASSERT(false, "Is not attached to FB");
+        return;
+    }
+
+    mAttachmentPoints.erase(point);
+}
+
+void
+WebGLFramebufferAttachable::NotifyFBsStatusChanged()
+{
+    AttachmentPoint* first = mAttachmentPoints.begin();
+    AttachmentPoint* last = mAttachmentPoints.end();
+    for ( ; first != last; ++first)
+        first->mFB->NotifyAttachableChanged();
+}