(not for review) Add overhang resource

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 619c18e6574fe057bb1356a87ff754d68c3196b5..70d8c45c564add7e83ea4afa268b8a56d5c6b47a 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -24,6 +24,7 @@
 #include "cc/input/top_controls_state.h"
 #include "cc/layers/layer_lists.h"
 #include "cc/output/output_surface.h"
+#include "cc/resources/scoped_ui_resource.h"
 #include "cc/resources/ui_resource_bitmap.h"
 #include "cc/resources/ui_resource_client.h"
 #include "cc/scheduler/rate_limiter.h"
@@ -379,6 +380,9 @@ class CC_EXPORT LayerTreeHost : NON_EXPORTED_BASE(public RateLimiterClient) {
   SkColor background_color_;
   bool has_transparent_background_;
 
+  scoped_refptr<UIResourceBitmap> overhang_bitmap_;
+  scoped_ptr<ScopedUIResource> overhang_ui_resource_;
+
   typedef ScopedPtrVector<PrioritizedResource> TextureList;
   size_t partial_texture_update_requests_;