cc: Enable composited border-radius scrolling.

cc/layers/layer.cc

 // Copyright 2010 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/layer.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 408 matching lines @@
   if (inputs_.mask_layer.get() == mask_layer)
     return;
   if (inputs_.mask_layer.get()) {
     DCHECK_EQ(this, inputs_.mask_layer->parent());
     inputs_.mask_layer->RemoveFromParent();
   }
   inputs_.mask_layer = mask_layer;
   if (inputs_.mask_layer.get()) {
     // The mask layer should not have any children.
     DCHECK(inputs_.mask_layer->children().empty());
+    DCHECK_EQ(bounds().ToString(), inputs_.mask_layer->bounds().ToString());

[trchen, 2017/05/22 23:00:06]

CLM updates layer geometry after attaching mask layer. I think this check should
be done during commit. Also I think this is a spin-off from another discussion.
Should we split this into a different CL?

[sunxd, 2017/06/15 15:59:10]

Done.

 
     inputs_.mask_layer->RemoveFromParent();
     DCHECK(!inputs_.mask_layer->parent());
     inputs_.mask_layer->SetParent(this);
     if (inputs_.filters.IsEmpty() &&
         (!layer_tree_host_ ||
          layer_tree_host_->GetSettings().enable_mask_tiling)) {
       inputs_.mask_layer->SetLayerMaskType(
           Layer::LayerMaskType::MULTI_TEXTURE_MASK);
     } else {
@@ skipping 988 matching lines @@
       ->subtree_has_copy_request;
 }
 
 gfx::Transform Layer::ScreenSpaceTransform() const {
   DCHECK_NE(transform_tree_index_, TransformTree::kInvalidNodeId);
   return draw_property_utils::ScreenSpaceTransform(
       this, layer_tree_host_->property_trees()->transform_tree);
 }
 
 }  // namespace cc