Fixing Canvas2DLayerBridge to handle lost graphics contexts

Source/core/platform/graphics/chromium/Canvas2DLayerBridge.h

Index: Source/core/platform/graphics/chromium/Canvas2DLayerBridge.h
diff --git a/Source/core/platform/graphics/chromium/Canvas2DLayerBridge.h b/Source/core/platform/graphics/chromium/Canvas2DLayerBridge.h
index 68388eadb874f0a53718cb3c890e0cf7d1901060..ed1969624f6ad9aef3ade0ca937c103c9760fe23 100644
--- a/Source/core/platform/graphics/chromium/Canvas2DLayerBridge.h
+++ b/Source/core/platform/graphics/chromium/Canvas2DLayerBridge.h
@@ -56,10 +56,7 @@ public:
         Threaded
     };
 
-    static PassOwnPtr<Canvas2DLayerBridge> create(PassRefPtr<GraphicsContext3D> context, SkDeferredCanvas* canvas, OpacityMode opacityMode, ThreadMode threading)
-    {
-        return adoptPtr(new Canvas2DLayerBridge(context, canvas, opacityMode, threading));
-    }
+    static PassOwnPtr<Canvas2DLayerBridge> create(PassRefPtr<GraphicsContext3D>, const IntSize&, OpacityMode, ThreadMode);
 
     virtual ~Canvas2DLayerBridge();
 
@@ -84,10 +81,14 @@ public:
 
     WebKit::WebLayer* layer();
     void contextAcquired();
+    SkCanvas* getCanvas() { return m_canvas; }
 
     unsigned backBufferTexture();
 
+    bool isValid();
+
 protected:
+    // Special constructor only used for unit testing

[Stephen White, 2013/07/04 16:11:56]

Nit: Is this comment stale? It looks like there's no longer a new constructor,
just this one.

[Justin Novosad, 2013/07/04 17:34:04]

Done.

     Canvas2DLayerBridge(PassRefPtr<GraphicsContext3D>, SkDeferredCanvas*, OpacityMode, ThreadMode);
 
     SkDeferredCanvas* m_canvas;
@@ -95,6 +96,7 @@ protected:
     RefPtr<GraphicsContext3D> m_context;
     size_t m_bytesAllocated;
     bool m_didRecordDrawCommand;
+    bool m_surfaceIsValid;
     int m_framesPending;
 
     friend class WTF::DoublyLinkedListNode<Canvas2DLayerBridge>;