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 90583d275b6ef70832078fa3d25718707e58b9fc..f231155f0c9739f71cd6aab92916d6b5cc94daae 100644
--- a/cc/resources/tile.h
+++ b/cc/resources/tile.h
@@ -132,9 +132,6 @@ 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;
@@ -164,7 +161,6 @@ 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_;