diff -r 000000000000 -r 6474c204b198 content/canvas/src/DocumentRendererParent.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/canvas/src/DocumentRendererParent.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,57 @@
+/* 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 "mozilla/ipc/DocumentRendererParent.h"
+#include "gfxImageSurface.h"
+#include "gfxPattern.h"
+#include "nsICanvasRenderingContextInternal.h"
+
+using namespace mozilla::ipc;
+
+DocumentRendererParent::DocumentRendererParent()
+{}
+
+DocumentRendererParent::~DocumentRendererParent()
+{}
+
+void DocumentRendererParent::SetCanvasContext(nsICanvasRenderingContextInternal* aCanvas,
+                                              gfxContext* ctx)
+{
+    mCanvas = aCanvas;
+    mCanvasContext = ctx;
+}
+
+void DocumentRendererParent::DrawToCanvas(const nsIntSize& aSize,
+                                          const nsCString& aData)
+{
+    if (!mCanvas || !mCanvasContext)
+        return;
+
+    nsRefPtr<gfxImageSurface> surf =
+        new gfxImageSurface(reinterpret_cast<uint8_t*>(const_cast<nsCString&>(aData).BeginWriting()),
+                            gfxIntSize(aSize.width, aSize.height),
+                            aSize.width * 4,
+                            gfxImageFormat::ARGB32);
+    nsRefPtr<gfxPattern> pat = new gfxPattern(surf);
+
+    gfxRect rect(gfxPoint(0, 0), gfxSize(aSize.width, aSize.height));
+    mCanvasContext->NewPath();
+    mCanvasContext->PixelSnappedRectangleAndSetPattern(rect, pat);
+    mCanvasContext->Fill();
+
+    // get rid of the pattern surface ref, because aData is very
+    // likely to go away shortly
+    mCanvasContext->SetColor(gfxRGBA(1,1,1,1));
+
+    gfxRect damageRect = mCanvasContext->UserToDevice(rect);
+    mCanvas->Redraw(damageRect);
+}
+
+bool
+DocumentRendererParent::Recv__delete__(const nsIntSize& renderedSize,
+                                       const nsCString& data)
+{
+    DrawToCanvas(renderedSize, data);
+    return true;
+}