Move occlusion info to TilePriority.

cc/resources/tile.h

Index: cc/resources/tile.h
diff --git a/cc/resources/tile.h b/cc/resources/tile.h
index 29acf80a1e35d116e309dde63d4a9f3c8d5aa1a3..69ef56fde8cd316d1b1024f9aff6fbf1e7723a5c 100644
--- a/cc/resources/tile.h
+++ b/cc/resources/tile.h
@@ -128,9 +128,6 @@ class CC_EXPORT Tile : public RefCountedManaged<Tile> {
     return managed_state_.tile_versions[mode];
   }
 
-  void set_is_occluded(bool is_occluded) { is_occluded_ = is_occluded; }
-  bool is_occluded() const { return is_occluded_; }
-
  private:
   friend class TileManager;
   friend class PrioritizedTileSet;
@@ -160,7 +157,6 @@ class CC_EXPORT Tile : public RefCountedManaged<Tile> {
   gfx::Rect content_rect_;
   float contents_scale_;
   gfx::Rect opaque_rect_;
-  bool is_occluded_;
 
   TilePriority priority_[NUM_TREES];
   ManagedTileState managed_state_;