ash/mash: Fix painting of status-tray bubble.

ui/views/mus/native_widget_mus.cc

 // Copyright 2015 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/views/mus/native_widget_mus.h"
 
 #include "base/macros.h"
 #include "base/thread_task_runner_handle.h"
 #include "components/mus/public/cpp/property_type_converters.h"
 #include "components/mus/public/cpp/window.h"
@@ skipping 454 matching lines @@
 
 gfx::NativeWindow NativeWidgetMus::GetNativeWindow() const {
   return content_;
 }
 
 Widget* NativeWidgetMus::GetTopLevelWidget() {
   return GetWidget();
 }
 
 const ui::Compositor* NativeWidgetMus::GetCompositor() const {
   return window_tree_host_->window()->layer()->GetCompositor();

[James Cook, 2016/04/06 03:44:16]

Drive-by question... I presume this doesn't need to change to
content_->layer()->GetCompositor() also?  I'm not familiar with the compositor
system, but I see lots of ways to get compositors:

window_tree_host_->compositor()
window_tree_host_->window()->layer()->GetCompositor()
content_->layer()->GetCompositor()

Are they all the same?

[sadrul, 2016/04/06 14:05:44]

Yes, the entire layer-tree share the same compositor, which is owned by the
WindowTreeHost instance the hosts the layer-tree.

I have changed this code to just use window_tree_host_->compositor() here, it's
simpler than having to go through the window()->layer()

 }
 
 const ui::Layer* NativeWidgetMus::GetLayer() const {
-  return window_tree_host_ ? window_tree_host_->window()->layer() : nullptr;
+  return content_ ? content_->layer() : nullptr;
 }
 
 void NativeWidgetMus::ReorderNativeViews() {
   // NOTIMPLEMENTED();
 }
 
 void NativeWidgetMus::ViewRemoved(View* view) {
   // NOTIMPLEMENTED();
 }
 
@@ skipping 512 matching lines @@
     window_tree_host_->Show();
     GetNativeWindow()->Show();
   } else {
     window_tree_host_->Hide();
     GetNativeWindow()->Hide();
   }
   native_widget_delegate_->OnNativeWidgetVisibilityChanged(window->visible());
 }
 
 }  // namespace views