Bug 1012213: Let the BufferRect be managed and cleared by the callers like before. r=mattwoodrow

gfx/layers/client/ContentClient.cpp

@@ -260,9 +260,6 @@ ContentClientRemoteBuffer::CreateBackBuffer(const nsIntRect& aBufferRect)
       return;
     }
   }
-
-  mBufferRect = aBufferRect;
-  mBufferRotation = nsIntPoint();
 }
 
 void