wip: not for commit (update twin relationship)

cc/layers/picture_layer.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/picture_layer.h"
 
 #include "base/auto_reset.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/picture_layer_impl.h"
 #include "cc/trees/layer_tree_impl.h"
@@ skipping 39 matching lines @@
     DCHECK_EQ(layer_impl->bounds().ToString(), pile_->tiling_size().ToString());
   }
 
   layer_impl->SetIsMask(is_mask_);
 
   // Unlike other properties, invalidation must always be set on layer_impl.
   // See PictureLayerImpl::PushPropertiesTo for more details.
   layer_impl->invalidation_.Clear();
   layer_impl->invalidation_.Swap(&pile_invalidation_);
   layer_impl->pile_ = PicturePileImpl::CreateFromOther(pile_.get());
+
+  // Update the twin relationship as soon as possible.
+  layer_impl->UpdateTwinRelationship();
 }
 
 void PictureLayer::SetLayerTreeHost(LayerTreeHost* host) {
   Layer::SetLayerTreeHost(host);
   if (host) {
     pile_->SetMinContentsScale(host->settings().minimum_contents_scale);
     pile_->SetTileGridSize(host->settings().default_tile_size);
     pile_->set_slow_down_raster_scale_factor(
         host->debug_state().slow_down_raster_scale_factor);
     pile_->set_show_debug_picture_borders(
@@ skipping 138 matching lines @@
 
 bool PictureLayer::HasDrawableContent() const {
   return client_ && Layer::HasDrawableContent();
 }
 
 void PictureLayer::RunMicroBenchmark(MicroBenchmark* benchmark) {
   benchmark->RunOnLayer(this);
 }
 
 }  // namespace cc