Bug 622072. Part 2: Add DidTransactionCallback to CanvasLayer. r=bas, sr=joe

gfx/layers/Layers.h

@@ -1181,6 +1181,16 @@ public:
    */
   void Updated() { mDirty = PR_TRUE; }
 
+  /**
+   * Register a callback to be called at the end of each transaction.
+   */
+  typedef void (* DidTransactionCallback)(void* aClosureData);
+  void SetDidTransactionCallback(DidTransactionCallback aCallback, void* aClosureData)
+  {
+    mCallback = aCallback;
+    mCallbackData = aClosureData;
+  }
+
   /**
    * CONSTRUCTION PHASE ONLY
    * Set the filter used to resample this image (if necessary).
@@ -1204,14 +1214,25 @@ public:
 
 protected:
   CanvasLayer(LayerManager* aManager, void* aImplData)
-    : Layer(aManager, aImplData), mFilter(gfxPattern::FILTER_GOOD), mDirty(PR_FALSE) {}
+    : Layer(aManager, aImplData),
+      mCallback(nsnull), mCallbackData(nsnull), mFilter(gfxPattern::FILTER_GOOD),
+      mDirty(PR_FALSE) {}
 
   virtual nsACString& PrintInfo(nsACString& aTo, const char* aPrefix);
 
+  void FireDidTransactionCallback()
+  {
+    if (mCallback) {
+      mCallback(mCallbackData);
+    }
+  }
+
   /**
    * 0, 0, canvaswidth, canvasheight
    */
   nsIntRect mBounds;
+  DidTransactionCallback mCallback;
+  void* mCallbackData;
   gfxPattern::GraphicsFilter mFilter;
   /**
    * Set to true in Updated(), cleared during a transaction.

gfx/layers/basic/BasicLayers.cpp

@@ -995,6 +995,7 @@ void
 BasicCanvasLayer::Paint(gfxContext* aContext)
 {
   UpdateSurface();
+  FireDidTransactionCallback();
   PaintWithOpacity(aContext, GetEffectiveOpacity());
 }
 

gfx/layers/d3d10/CanvasLayerD3D10.cpp

@@ -228,10 +228,10 @@ void
 CanvasLayerD3D10::RenderLayer()
 {
   UpdateSurface();
+  FireDidTransactionCallback();
 
-  if (!mTexture) {
+  if (!mTexture)
     return;
-  }
 
   nsIntRect visibleRect = mVisibleRegion.GetBounds();
 

gfx/layers/d3d9/CanvasLayerD3D9.cpp

@@ -209,6 +209,8 @@ void
 CanvasLayerD3D9::RenderLayer()
 {
   UpdateSurface();
+  FireDidTransactionCallback();
+
   if (!mTexture)
     return;
 

gfx/layers/opengl/CanvasLayerOGL.cpp

@@ -184,6 +184,7 @@ CanvasLayerOGL::RenderLayer(int aPreviousDestination,
                             const nsIntPoint& aOffset)
 {
   UpdateSurface();
+  FireDidTransactionCallback();
 
   mOGLManager->MakeCurrent();