[ash-md] Doesn't recreate a rounded rect mask for overview windows

ui/compositor/layer.cc

 // Copyright (c) 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 "ui/compositor/layer.h"
 
 #include <algorithm>
 #include <memory>
 #include <utility>
 
@@ skipping 655 matching lines @@
   return cc_layer_->background_color();
 }
 
 bool Layer::SchedulePaint(const gfx::Rect& invalid_rect) {
   if ((type_ == LAYER_SOLID_COLOR && !texture_layer_.get()) ||
       type_ == LAYER_NINE_PATCH || (!delegate_ && !mailbox_.IsValid()))
     return false;
 
   damaged_region_.Union(invalid_rect);
   ScheduleDraw();
+
+  if (layer_mask_) {
+    layer_mask_->damaged_region_.Union(invalid_rect);
+    layer_mask_->ScheduleDraw();
+  }
   return true;
 }
 
 void Layer::ScheduleDraw() {
   Compositor* compositor = GetCompositor();
   if (compositor)
     compositor->ScheduleDraw();
 }
 
 void Layer::SendDamagedRects() {
   if (damaged_region_.IsEmpty())
     return;
   if (!delegate_ && !mailbox_.IsValid())
     return;
 
   for (cc::Region::Iterator iter(damaged_region_); iter.has_rect(); iter.next())
     cc_layer_->SetNeedsDisplayRect(iter.rect());
+  if (layer_mask_)
+    layer_mask_->SendDamagedRects();
 
   if (content_layer_)
     paint_region_.Union(damaged_region_);
   damaged_region_.Clear();
 }
 
 void Layer::CompleteAllAnimations() {
   typedef std::vector<scoped_refptr<LayerAnimator> > LayerAnimatorVector;
   LayerAnimatorVector animators;
   CollectAnimators(&animators);
@@ skipping 348 matching lines @@
   if (animator_) {
     animator_->ResetCompositor(compositor);
     animator_->RemoveFromCollection(collection);
   }
 
   for (auto* child : children_)
     child->ResetCompositorForAnimatorsInTree(compositor);
 }
 
 }  // namespace ui