Make stream captures work on canvases that are not in the DOM.

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h

Index: third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
diff --git a/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h b/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
index a3d8bf63ceb50ea8dabc71bcc7d12a6e447d5353..aafdef9d98a850ba6af56aaa9a5e10ec334dca0d 100644
--- a/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
+++ b/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
@@ -110,7 +110,8 @@ class PLATFORM_EXPORT Canvas2DLayerBridge
                        bool lostResource);
 
   // ImageBufferSurface implementation
-  void finalizeFrame(const FloatRect& dirtyRect);
+  void finalizeFrame();
+  void doPaintInvalidation(const FloatRect& dirtyRect);
   void willWritePixels();
   void willOverwriteAllPixels();
   void willOverwriteCanvas();
@@ -131,7 +132,6 @@ class PLATFORM_EXPORT Canvas2DLayerBridge
                    int y);
   void flush();
   void flushGpu();
-  void prepareSurfaceForPaintingIfNeeded();
   bool isHidden() { return m_isHidden; }
   OpacityMode opacityMode() { return m_opacityMode; }
   void dontUseIdleSchedulingForTesting() {