cc: Add PictureLayerTilingSet to manage PictureLayerTiling

cc/picture_layer.cc

Index: cc/picture_layer.cc
diff --git a/cc/picture_layer.cc b/cc/picture_layer.cc
index 01eb454b4d8ab0ce67b9c60486ebcee3eb14ea7d..fe93950f682d67548aab3b4a891b71c27a4beaea 100644
--- a/cc/picture_layer.cc
+++ b/cc/picture_layer.cc
@@ -31,13 +31,14 @@ void PictureLayer::pushPropertiesTo(LayerImpl* base_layer) {
   PictureLayerImpl* layer_impl = static_cast<PictureLayerImpl*>(base_layer);
   pile_.PushPropertiesTo(layer_impl->pile_);
 
-  // TODO(enne): Need to sync tiling from active tree prior to this?
-  // TODO(nduca): Need to invalidate tiles here from pile's invalidation info.
+  // TODO(enne): Need to sync tiling from active tree prior to this.
+  layer_impl->tilings_.Invalidate(invalidation_);
+  invalidation_.Clear();
 }
 
 void PictureLayer::setNeedsDisplayRect(const gfx::RectF& layer_rect) {
   gfx::Rect rect = gfx::ToEnclosedRect(layer_rect);
-  pile_.Invalidate(rect);
+  invalidation_.Union(rect);
 }
 
 void PictureLayer::update(ResourceUpdateQueue&, const OcclusionTracker*,