Aura: Support hovering restore & close buttons for full screen apps

ui/views/widget/native_widget_aura.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/views/widget/native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/string_util.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/aura/client/activation_client.h"
@@ skipping 224 matching lines @@
   }
 
   aura::client::SetActivationDelegate(window_, this);
 }
 
 NonClientFrameView* NativeWidgetAura::CreateNonClientFrameView() {
   return NULL;
 }
 
 void NativeWidgetAura::UpdateFrameAfterFrameChange() {
-  // We don't support changing the frame type.
-  NOTREACHED();
 }
 
 bool NativeWidgetAura::ShouldUseNativeFrame() const {
   // There is only one frame type for aura.
   return false;
 }
 
 void NativeWidgetAura::FrameTypeChanged() {
   // This is called when the Theme has changed; forward the event to the root
   // widget.
@@ skipping 691 matching lines @@
   }
 }
 
 // static
 bool NativeWidgetPrivate::IsMouseButtonDown() {
   return aura::RootWindow::GetInstance()->IsMouseButtonDown();
 }
 
 }  // namespace internal
 }  // namespace views