cc: Move image decodes from tile manager to a separate file.

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 a69e5a27dcf20122c9ffb362e85374364b8575af..f06ab7126bf2b0a6dc9b75ac36cbc9c04c8a0d7c 100644
--- a/cc/tiles/tile_manager.h
+++ b/cc/tiles/tile_manager.h
@@ -20,6 +20,7 @@
 #include "cc/resources/memory_history.h"
 #include "cc/resources/resource_pool.h"
 #include "cc/tiles/eviction_tile_priority_queue.h"
+#include "cc/tiles/image_decode_controller.h"
 #include "cc/tiles/raster_tile_priority_queue.h"
 #include "cc/tiles/tile.h"
 #include "cc/tiles/tile_draw_info.h"
@@ -252,9 +253,6 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
     int resource_count_;
   };
 
-  void OnImageDecodeTaskCompleted(int layer_id,
-                                  SkPixelRef* pixel_ref,
-                                  bool was_canceled);
   void OnRasterTaskCompleted(Tile::Id tile,
                              scoped_ptr<ScopedResource> resource,
                              const RasterSource::SolidColorAnalysis& analysis,
@@ -265,8 +263,6 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
 
   void FreeResourcesForTile(Tile* tile);
   void FreeResourcesForTileAndNotifyClientIfTileWasReadyToDraw(Tile* tile);
-  scoped_refptr<ImageDecodeTask> CreateImageDecodeTask(Tile* tile,
-                                                       SkPixelRef* pixel_ref);
   scoped_refptr<RasterTask> CreateRasterTask(
       const PrioritizedTile& prioritized_tile);
 
@@ -302,13 +298,7 @@ class CC_EXPORT TileManager : public TileTaskRunnerClient {
   bool did_check_for_completed_tasks_since_last_schedule_tasks_;
   bool did_oom_on_last_assign_;
 
-  typedef base::hash_map<uint32_t, scoped_refptr<ImageDecodeTask>>
-      PixelRefTaskMap;
-  typedef base::hash_map<int, PixelRefTaskMap> LayerPixelRefTaskMap;
-  LayerPixelRefTaskMap image_decode_tasks_;
-
-  typedef base::hash_map<int, int> LayerCountMap;
-  LayerCountMap used_layer_counts_;
+  ImageDecodeController image_decode_controller_;
 
   RasterTaskCompletionStats flush_stats_;