Revert "cc: Remove layers that are not drawn from tile manager."

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index fc6a204493aeeb9a7a57684067f3d40c8eff1742..6b2a0759e0d6480ab8acfc78f4069595e0b4da9a 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -359,16 +359,10 @@ void PictureLayerImpl::AppendQuads(QuadSink* quad_sink,
 }
 
 void PictureLayerImpl::DidUnregisterLayer() {
-  TRACE_EVENT0("cc", "PictureLayerImpl::DidUnregisterLayer");
-
   layer_needs_to_register_itself_ = true;
-  RemoveAllTilings();
 }
 
 void PictureLayerImpl::UpdateTilePriorities() {
-  TRACE_EVENT0("cc", "PictureLayerImpl::UpdateTilePriorities");
-
-  DCHECK(IsDrawnRenderSurfaceLayerListMember());
   DCHECK(!needs_post_commit_initialization_);
   CHECK(should_update_tile_priorities_);