cc: Eliminate refcount churn in prioritized tile's raster source.

cc/tiles/prioritized_tile.h

Index: cc/tiles/prioritized_tile.h
diff --git a/cc/tiles/prioritized_tile.h b/cc/tiles/prioritized_tile.h
index 1d7ad9212db2868c9d68dac14122eb7144c2a752..c8ee76dcd7150047f8bda74d1c4551941aebb804 100644
--- a/cc/tiles/prioritized_tile.h
+++ b/cc/tiles/prioritized_tile.h
@@ -7,6 +7,7 @@
 
 #include "cc/base/cc_export.h"
 #include "cc/playback/raster_source.h"
+#include "cc/tiles/picture_layer_tiling.h"
 #include "cc/tiles/tile.h"
 #include "cc/tiles/tile_priority.h"
 
@@ -19,16 +20,11 @@ class CC_EXPORT PrioritizedTile {
   // This class is constructed and returned by a |PictureLayerTiling|, and
   // represents a tile and its priority.
   PrioritizedTile();
-  PrioritizedTile(const PrioritizedTile& other);

[danakj, 2016/07/14 21:19:08]

Can it be DISALLOW_COPY_AND_ASSIGN?

[vmpstr, 2016/07/14 21:27:41]

No, it's still being copied...

-  PrioritizedTile(PrioritizedTile&& other);
   ~PrioritizedTile();
 
-  PrioritizedTile& operator=(const PrioritizedTile& other);
-  PrioritizedTile& operator=(PrioritizedTile&& other);
-
   Tile* tile() const { return tile_; }
   const scoped_refptr<RasterSource>& raster_source() const {
-    return raster_source_;
+    return source_tiling_->raster_source();
   }
   const TilePriority& priority() const { return priority_; }
   bool is_occluded() const { return is_occluded_; }
@@ -39,14 +35,14 @@ class CC_EXPORT PrioritizedTile {
   friend class PictureLayerTiling;

[danakj, 2016/07/14 21:19:08]

can it be gone?

[vmpstr, 2016/07/14 21:27:41]

Done.

 
   PrioritizedTile(Tile* tile,

[danakj, 2016/07/14 21:19:08]

can it be public?

[vmpstr, 2016/07/14 21:27:40]

Done.

-                  scoped_refptr<RasterSource> raster_source,
+                  const PictureLayerTiling* source_tiling,
                   const TilePriority priority,
                   bool is_occluded);
 
-  Tile* tile_;
-  scoped_refptr<RasterSource> raster_source_;
+  Tile* tile_ = nullptr;
+  const PictureLayerTiling* source_tiling_ = nullptr;
   TilePriority priority_;
-  bool is_occluded_;
+  bool is_occluded_ = false;
 };
 
 }  // namespace cc