Bug 672755 - Add memory reporters for decoded video and audio queues. r=cpearce r=joe

gfx/layers/ImageLayers.h

@@ -454,6 +454,11 @@ public:
 
   virtual PRUint8* AllocateBuffer(PRUint32 aSize);
 
+  /**
+   * Return the number of bytes of heap memory used to store this image.
+   */
+  virtual PRUint32 GetDataSize() = 0;
+
 protected:
   PlanarYCbCrImage(void* aImplData) : Image(aImplData, PLANAR_YCBCR) {}
 };