cc: Update picture pile on tiles to prevent memory leak

cc/picture_layer_impl.cc

Index: cc/picture_layer_impl.cc
diff --git a/cc/picture_layer_impl.cc b/cc/picture_layer_impl.cc
index 2aef705e60c6ab235cb63ed56b23805b69193d4e..fd18e5209a7d2b1f1829b45bf201fd39c79255fb 100644
--- a/cc/picture_layer_impl.cc
+++ b/cc/picture_layer_impl.cc
@@ -180,7 +180,7 @@ void PictureLayerImpl::didUpdateTransforms() {
 }
 
 void PictureLayerImpl::didBecomeActive() {
-  tilings_.MoveTilePriorities(PENDING_TREE, ACTIVE_TREE);
+  tilings_.DidBecomeActive();
 }
 
 void PictureLayerImpl::didLoseOutputSurface() {
@@ -237,6 +237,10 @@ scoped_refptr<Tile> PictureLayerImpl::CreateTile(PictureLayerTiling* tiling,
       tiling->contents_scale()));
 }
 
+void PictureLayerImpl::UpdatePile(Tile* tile) {
+  tile->set_picture_pile(pile_);
+}
+
 void PictureLayerImpl::SyncFromActiveLayer() {
   DCHECK(layerTreeImpl()->IsPendingTree());
   if (!drawsContent())