VrShell: Add test for fullscreen transitions.

chrome/browser/android/vr_shell/ui_scene_manager.h

 // Copyright 2016 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_ANDROID_VR_SHELL_UI_SCENE_MANAGER_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_SCENE_MANAGER_H_
 
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/timer/timer.h"
 #include "base/values.h"
 #include "chrome/browser/android/vr_shell/ui_interface.h"
 
 class GURL;
 
 namespace vr_shell {
 
@@ skipping 50 matching lines @@
   bool content_rendering_enabled_ = true;
 
   int next_available_id_ = 1;
 
   std::vector<UiElement*> browser_ui_elements_;
 
   base::OneShotTimer security_warning_timer_;
 
   base::WeakPtrFactory<UiSceneManager> weak_ptr_factory_;
 
+  FRIEND_TEST_ALL_PREFIXES(UiSceneManagerTest, UiUpdatesForFullscreen);
+
   DISALLOW_COPY_AND_ASSIGN(UiSceneManager);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_SCENE_MANAGER_H_