Pause drawing webvr when the App button is pressed

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/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/timer/timer.h"
 #include "base/values.h"
 
 namespace vr_shell {
 
 struct UiElement;
 class UiScene;
+class VrThreadEnvoy;
 
 class UiSceneManager {
  public:
-  explicit UiSceneManager(UiScene* scene);
+  UiSceneManager(const base::WeakPtr<VrThreadEnvoy>& weak_vr_gl_thread,
+                 UiScene* scene);
   ~UiSceneManager();
 
   base::WeakPtr<UiSceneManager> GetWeakPtr();
 
   void SetWebVRSecureOrigin(bool secure);
   void SetWebVRMode(bool web_vr);
 
+  void AppButtonPressed();
+
  private:
   void ConfigureSecurityWarnings();
   void OnSecurityWarningTimer();
   void OnGLInitialized();
 
+  base::WeakPtr<VrThreadEnvoy> weak_vr_thread_envoy_;
   UiScene* scene_;
 
   // UI element pointers (not owned by the scene manager).
   UiElement* permanent_security_warning_ = nullptr;
   UiElement* transient_security_warning_ = nullptr;
   UiElement* main_content_ = nullptr;
 
   bool web_vr_mode_ = false;
   bool secure_origin_ = false;
+  bool content_rendering_enabled_ = false;
 
   base::OneShotTimer security_warning_timer_;
 
   base::WeakPtrFactory<UiSceneManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UiSceneManager);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_SCENE_MANAGER_H_