Support different formats in the same resource pool.

cc/resources/tile_manager.h

Index: cc/resources/tile_manager.h
diff --git a/cc/resources/tile_manager.h b/cc/resources/tile_manager.h
index 3ae97159828a35e11f9dcfb4f02521e663b79a3f..f4ce117506028cc71234d27af0030d9b5e901289 100644
--- a/cc/resources/tile_manager.h
+++ b/cc/resources/tile_manager.h
@@ -136,8 +136,8 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient,
   void InitializeTilesWithResourcesForTesting(const std::vector<Tile*>& tiles) {
     for (size_t i = 0; i < tiles.size(); ++i) {
       TileDrawInfo& draw_info = tiles[i]->draw_info();
-      draw_info.resource_ =
-          resource_pool_->AcquireResource(tiles[i]->desired_texture_size());
+      draw_info.resource_ = resource_pool_->AcquireResource(
+          tiles[i]->desired_texture_size(), FORMAT_USAGE_NATIVE);
     }
   }
 
@@ -238,6 +238,7 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient,
                           scoped_ptr<ScopedResource> resource,
                           const RasterSource::SolidColorAnalysis& analysis);
 
+  ResourceFormatUsage DetermineResourceFormatUsage(const Tile* tile) const;
   void FreeResourcesForTile(Tile* tile);
   void FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(Tile* tile);
   scoped_refptr<ImageDecodeTask> CreateImageDecodeTask(Tile* tile,