cc: Add PictureLayerTiling for impl-side painting

cc/tile.h

Index: cc/tile.h
diff --git a/cc/tile.h b/cc/tile.h
index 2f555c339514fe398993594356f398886ae2f660..1985fa2c488808481169d82f05d2c93f4bf220cc 100644
--- a/cc/tile.h
+++ b/cc/tile.h
@@ -73,6 +73,10 @@ class Tile : public base::RefCounted<Tile> {
   // Returns 0 if not drawable.
   ResourceProvider::ResourceId GetDrawableResourceId(int frame_number);
 
+  const gfx::Rect& opaque_rect() const { return opaque_rect_; }
+  // TODO(enne): Make this real
+  bool contents_swizzled() const { return false; }
+
  protected:
   // Methods called by TileManager.
   void DeleteVersionOnRequestOfTileManager(int frame_number);
@@ -88,6 +92,7 @@ class Tile : public base::RefCounted<Tile> {
   gfx::Rect tile_size_;
   GLenum format_;
   gfx::Rect rect_inside_picture_;
+  gfx::Rect opaque_rect_;
   TileQuality quality_;
   ScopedVector<TileVersion> versions_;
 };