Bug 739679 - Part 6: Fix unlocking gfxReusableSurface. r=pcwalton

gfx/layers/TiledLayerBuffer.h

@@ -116,8 +116,6 @@ protected:
   int             mRetainedHeight; // in tiles
 
 private:
-  TiledLayerBuffer(const TiledLayerBuffer&) MOZ_DELETE;
-
   const Derived& AsDerived() const { return *static_cast<const Derived*>(this); }
   Derived& AsDerived() { return *static_cast<Derived*>(this); }
 

gfx/layers/basic/BasicTiledThebesLayer.h

@@ -79,6 +79,9 @@ class BasicTiledLayerBuffer : public TiledLayerBuffer<BasicTiledLayerBuffer, Bas
   friend class TiledLayerBuffer<BasicTiledLayerBuffer, BasicTiledLayerTile>;
 
 public:
+  BasicTiledLayerBuffer()
+    {}
+
   void PaintThebes(BasicTiledThebesLayer* aLayer,
                    const nsIntRegion& aNewValidRegion,
                    const nsIntRegion& aPaintRegion,

gfx/layers/opengl/TiledThebesLayerOGL.cpp

@@ -136,6 +136,12 @@ TiledThebesLayerOGL::ProcessUploadQueue()
   mValidRegion = mVideoMemoryTiledBuffer.GetValidRegion();
 
   mMainMemoryTiledBuffer.ReadUnlock();
+  // Release all the tiles by replacing the tile buffer with an empty
+  // tiled buffer. This will prevent us from doing a double unlock when
+  // calling  ~TiledThebesLayerOGL.
+  // FIXME: This wont be needed when we do progressive upload and lock
+  // tile by tile.
+  mMainMemoryTiledBuffer = BasicTiledLayerBuffer();
   mRegionToUpload = nsIntRegion();
 
 }

gfx/thebes/gfxReusableSurfaceWrapper.cpp

@@ -48,6 +48,7 @@ void
 gfxReusableSurfaceWrapper::ReadUnlock()
 {
   PR_ATOMIC_DECREMENT(&mReadCount);
+  NS_ABORT_IF_FALSE(mReadCount >= 0, "Should not be negative");
 }
 
 gfxReusableSurfaceWrapper*