cc: Only register live tiles with the TileManager

cc/picture_layer_tiling.h

Index: cc/picture_layer_tiling.h
diff --git a/cc/picture_layer_tiling.h b/cc/picture_layer_tiling.h
index d2330a1bc603d4cc1b0ff822995f358ab87d5689..e8e3b44222dbd82ecc4929b026cfd0fa2d5014aa 100644
--- a/cc/picture_layer_tiling.h
+++ b/cc/picture_layer_tiling.h
@@ -38,6 +38,8 @@ class TileHandle {
  public:
   TileHandle(scoped_refptr<Tile> tile);
   Tile* tile() const { return tile_.get(); }
+  void RegisterWithTileManager();
+  void UnregisterFromTileManager();
  private:
   scoped_refptr<Tile> tile_;
   scoped_refptr<ManagedTileState> managed_tile_state_;
@@ -67,6 +69,12 @@ class CC_EXPORT PictureLayerTiling {
   gfx::SizeF ContentSizeF() const;
   float contents_scale() const { return contents_scale_; }
 
+  void RegisterAllTilesManagedForTesting() {
+    for (TileMap::iterator it = tiles_.begin();
+         it != tiles_.end(); ++it)
+      it->second.RegisterWithTileManager();
+  }
+
   std::vector<Tile*> AllTilesForTesting() const {
     std::vector<Tile*> all_tiles;
     for (TileMap::const_iterator it = tiles_.begin();