cc: Change Tile::tile_size_ from a Rect to a Size.

cc/resources/tile.h

Index: cc/resources/tile.h
diff --git a/cc/resources/tile.h b/cc/resources/tile.h
index 01a733cc6c9b9263046c8e2caeabd1c44bb0168a..6588ac56e6b276c0eff04cfc74cf4653ad8518f7 100644
--- a/cc/resources/tile.h
+++ b/cc/resources/tile.h
@@ -138,7 +138,7 @@ class CC_EXPORT Tile : public RefCountedManaged<Tile> {
 
   size_t GPUMemoryUsageInBytes() const;
 
-  gfx::Size size() const { return tile_size_.size(); }
+  gfx::Size size() const { return size_; }
 
   RasterMode DetermineRasterModeForTree(WhichTree tree) const;
   RasterMode DetermineOverallRasterMode() const;
@@ -178,7 +178,7 @@ class CC_EXPORT Tile : public RefCountedManaged<Tile> {
 
   TileManager* tile_manager_;
   scoped_refptr<PicturePileImpl> picture_pile_;
-  gfx::Rect tile_size_;
+  gfx::Size size_;
   gfx::Rect content_rect_;
   float contents_scale_;
   gfx::Rect opaque_rect_;