Improves first run dialog performance on Win8

chrome/browser/ui/webui/set_as_default_browser_ui.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_SET_AS_DEFAULT_BROWSER_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_SET_AS_DEFAULT_BROWSER_UI_H_
 
 #include "base/macros.h"
+#include "ui/views/widget/widget.h"
 #include "ui/web_dialogs/web_dialog_ui.h"
 
 class Browser;
 class Profile;
 
 // The UI used in first-run flow to prompt the user to set Chrome as the
 // default Windows browser and *the browser* of Metro mode. Intended for
 // Windows 8 only.
 class SetAsDefaultBrowserUI : public ui::WebDialogUI {
  public:
   explicit SetAsDefaultBrowserUI(content::WebUI* web_ui);
 
   // Present metroizer UI either in a new singleton tab or in a dialog window.
   static void Show(Profile* profile, Browser* browser);
 
+  // Returns the web dialog widget for testing.
+  static views::Widget* GetDialogWidgetForTesting();

[sky, 2016/07/06 19:21:19]

Instead of exposing this can you make Show() return the widget? Alternatively
add a function you can call to see if visible.

[zmin, 2016/07/06 20:04:31]

Yes, I can. However, the challenge is the browser test won't call show()
directly. It's trigged by "ForceFirstRun" command line flag during the test.

Also, I need the widget not only for visible but also for closing it in the
browser test.

[sky, 2016/07/06 23:53:16]

Would an IsVisible() function work on this class? Can you get a handle to the
instance?
Won't it be torn down by the test?

[zmin, 2016/07/18 21:12:14]

There is no instance of SetAsDefaultBrowserUI created during the first run of
Chrome. ::Show() as a static function is the only used API. The instance of real
WebDialog is created by a second class(SetAsDefaultBrowserDialogImpl) who is
declared in the anonymous namespace of .cc file. Also, SetAsDefaultBrowserUI
does not even store the pointer of SetAsDefaultBrowserDialogImpl. The second
class just deleted itself when the dialog is closed.
It needs to be closed before tear down so I can verify the re-show of main
window.

+
  private:
   DISALLOW_COPY_AND_ASSIGN(SetAsDefaultBrowserUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SET_AS_DEFAULT_BROWSER_UI_H_