V2 app support step2 : Use NativeAppWindow for Activity's window.

athena/content/web_activity.cc

 // Copyright 2014 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 "athena/content/web_activity.h"
 
 #include "athena/activity/public/activity_factory.h"
 #include "athena/activity/public/activity_manager.h"
 #include "athena/content/public/dialogs.h"
 #include "athena/input/public/accelerator_manager.h"
@@ skipping 454 matching lines @@
       MakeInvisible();
       ReloadAndObserve();
     } else {
       // If not previously specified, we change the state now to invisible..
       SetCurrentState(ACTIVITY_INVISIBLE);
     }
   }
   return web_view_;
 }
 
+views::Widget* WebActivity::CreateWidget() {
+  return NULL;  // Use default widget.
+}
+
 void WebActivity::CreateOverviewModeImage() {
   // TODO(skuhne): Create an overview.
 }
 
 gfx::ImageSkia WebActivity::GetOverviewModeImage() {
   return overview_mode_image_;
 }
 
 void WebActivity::PrepareContentsForOverview() {
   // Turn on fast resizing to avoid re-laying out the web contents when
@@ skipping 56 matching lines @@
 
 void WebActivity::ReloadAndObserve() {
   if (web_view_->IsContentEvicted()) {
     DCHECK_EQ(ACTIVITY_UNLOADED, current_state_);
     web_view_->ReloadContent();
   }
   Observe(web_view_->GetWebContents());
 }
 
 }  // namespace athena