Do not call StackWindowFrontOf() when the AppActivity's window is already at the top

athena/content/app_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/app_activity.h"
 
 #include "athena/activity/public/activity_manager.h"
 #include "athena/content/app_activity_registry.h"
 #include "athena/content/content_proxy.h"
 #include "athena/content/media_utils.h"
@@ skipping 102 matching lines @@
     // If the proxy was the active window, its deletion will cause a window
     // reordering since the next activatable window in line will move up to the
     // front. Since the application window is still hidden at this time, it is
     // not yet activatable and the window behind it will move to the front.
     if (wm::IsActiveWindow(app_proxy->GetWindow())) {
       // Delete the proxy window first and then move the new window to the top
       // of the stack, replacing the proxy window. Note that by deleting the
       // proxy the activation will change to the next (activatable) object and
       // thus we have to move the window in front at the end.
       Activity::Delete(app_proxy);
-      window_list_provider->StackWindowFrontOf(
-          GetWindow(),
-          window_list_provider->GetWindowList().back());
+      if (GetWindow() != window_list_provider->GetWindowList().back()) {
+        window_list_provider->StackWindowFrontOf(
+            GetWindow(),
+            window_list_provider->GetWindowList().back());
+      }
     } else {
       // The app window goes in front of the proxy window (we need to first
       // place the window before we can delete it).
       window_list_provider->StackWindowFrontOf(GetWindow(),
                                                app_proxy->GetWindow());
       Activity::Delete(app_proxy);
     }
     // The proxy should now be deleted.
     DCHECK(!app_activity_registry_->unloaded_activity_proxy());
   }
@@ skipping 99 matching lines @@
 void AppActivity::HideContentProxy() {
   content_proxy_.reset();
 }
 
 void AppActivity::ShowContentProxy() {
   if (!content_proxy_.get() && web_view_)
     content_proxy_.reset(new ContentProxy(web_view_));
 }
 
 }  // namespace athena