cc: Optimize decode scheduling for checker-images.

cc/tiles/tile_manager.h

Index: cc/tiles/tile_manager.h
diff --git a/cc/tiles/tile_manager.h b/cc/tiles/tile_manager.h
index 36234178f2d12d949e4528cef3090af610cccf53..be6de6d4c2b1729f8bd801606357617018461a42 100644
--- a/cc/tiles/tile_manager.h
+++ b/cc/tiles/tile_manager.h
@@ -282,7 +282,8 @@ class CC_EXPORT TileManager : CheckerImageTrackerClient {
   void FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(Tile* tile);
   scoped_refptr<TileTask> CreateRasterTask(
       const PrioritizedTile& prioritized_tile,
-      const gfx::ColorSpace& color_space);
+      const gfx::ColorSpace& color_space,
+      CheckerImageTracker::ImageDecodeQueue* checker_image_decode_queue);
 
   std::unique_ptr<EvictionTilePriorityQueue>
   FreeTileResourcesUntilUsageIsWithinLimit(
@@ -321,6 +322,12 @@ class CC_EXPORT TileManager : CheckerImageTrackerClient {
 
   void CheckPendingGpuWorkTiles(bool issue_signals);
 
+  void FilterImagesForCheckering(

[vmpstr, 2017/03/17 18:32:13]

Can you add tests for this function?

+      const PrioritizedTile& prioritized_tile,
+      std::vector<DrawImage>* images_to_decode,
+      ImageIdFlatSet* checker_images,
+      CheckerImageTracker::ImageDecodeQueue* checker_image_decode_queue);
+
   TileManagerClient* client_;
   base::SequencedTaskRunner* task_runner_;
   ResourcePool* resource_pool_;