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

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index 452d9b45ccfa5e65bdc444bdb3c3f36cc616f429..2ef8d845a78411a1b44d73136df6911fc2ad5a61 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -1026,7 +1026,7 @@ scoped_refptr<RasterTask> TileManager::CreateRasterTask(Tile* tile) {
   ManagedTileState& mts = tile->managed_state();
 
   scoped_ptr<ScopedResource> resource =
-      resource_pool_->AcquireResource(tile->tile_size_.size());
+      resource_pool_->AcquireResource(tile->size());
   const ScopedResource* const_resource = resource.get();
 
   // Create and queue all image decode tasks that this tile depends on.