Makes tile-creation lazy

cc/resources/picture_layer_tiling_set.h

Index: cc/resources/picture_layer_tiling_set.h
diff --git a/cc/resources/picture_layer_tiling_set.h b/cc/resources/picture_layer_tiling_set.h
index a619a1e093df195caa551b24effb5b888526aae1..13751670ab3f57d56fa46c129ee9ada6ae0de651 100644
--- a/cc/resources/picture_layer_tiling_set.h
+++ b/cc/resources/picture_layer_tiling_set.h
@@ -22,15 +22,12 @@ class CC_EXPORT PictureLayerTilingSet {
   // Shallow copies all data (except client and bounds from other).
   void CloneAll(
      const PictureLayerTilingSet& other,
-     const Region& invalidation,
      float minimum_contents_scale);
-  void Clone(const PictureLayerTiling* tiling, const Region& invalidation);
+  void Clone(const PictureLayerTiling* tiling);
 
   void SetLayerBounds(gfx::Size layer_bounds);
   gfx::Size LayerBounds() const;
 
-  void Invalidate(const Region& layer_invalidation);
-
   PictureLayerTiling* AddTiling(float contents_scale);
   size_t num_tilings() const { return tilings_.size(); }
   PictureLayerTiling* tiling_at(size_t idx) { return tilings_[idx]; }
@@ -47,9 +44,6 @@ class CC_EXPORT PictureLayerTilingSet {
   // Remove all tiles; keep all tilings.
   void RemoveAllTiles();
 
-  // For all tilings, create any tile that intersects |layer_rect|.
-  void CreateTilesFromLayerRect(gfx::Rect layer_rect);
-
   void UpdateTilePriorities(
       WhichTree tree,
       gfx::Size device_viewport,