Pause drawing webvr when the App button is pressed

chrome/browser/android/vr_shell/ui_scene_manager.h

Index: chrome/browser/android/vr_shell/ui_scene_manager.h
diff --git a/chrome/browser/android/vr_shell/ui_scene_manager.h b/chrome/browser/android/vr_shell/ui_scene_manager.h
index 62f2f98ac8e0917278ecbe0a448faec751968b12..114247183730ded8626722ff78678b2ed7a68be2 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager.h
+++ b/chrome/browser/android/vr_shell/ui_scene_manager.h
@@ -14,10 +14,12 @@ 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();
@@ -25,11 +27,14 @@ class UiSceneManager {
   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).
@@ -39,6 +44,7 @@ class UiSceneManager {
 
   bool web_vr_mode_ = false;
   bool secure_origin_ = false;
+  bool content_rendering_enabled_ = false;
 
   base::OneShotTimer security_warning_timer_;