Bug 564991. Part 8: Hoist GetLayerType out of individual layer manager types and make it available for all layers. r=jrmuizel,sr=vlad

gfx/layers/ImageLayers.h

@@ -198,6 +198,8 @@ public:
   ImageContainer* GetContainer() { return mContainer; }
   gfxPattern::GraphicsFilter GetFilter() { return mFilter; }
 
+  NS_LAYER_DECL_NAME("ImageLayer", TYPE_IMAGE)
+
 protected:
   ImageLayer(LayerManager* aManager, void* aImplData)
     : Layer(aManager, aImplData), mFilter(gfxPattern::FILTER_GOOD) {}