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 72a8ab30d796209265422741e82c0f0eec044be8..5eae531aab7b8a495e15b0b65354ae89c8fd0ee8 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager.h
+++ b/chrome/browser/android/vr_shell/ui_scene_manager.h
@@ -14,10 +14,11 @@ namespace vr_shell {
 
 struct UiElement;
 class UiScene;
+class VrBrowserInterface;
 
 class UiSceneManager {
  public:
-  explicit UiSceneManager(UiScene* scene);
+  UiSceneManager(VrBrowserInterface* browser, UiScene* scene);
   ~UiSceneManager();
 
   base::WeakPtr<UiSceneManager> GetWeakPtr();
@@ -25,6 +26,8 @@ class UiSceneManager {
   void SetWebVRSecureOrigin(bool secure);
   void SetWebVRMode(bool web_vr);
 
+  void OnAppButtonClicked();
+
  private:
   void CreateSecurityWarnings();
   void CreateContentQuad();
@@ -34,6 +37,7 @@ class UiSceneManager {
   void OnSecurityWarningTimer();
   int AllocateId();
 
+  VrBrowserInterface* browser_;
   UiScene* scene_;
 
   // UI element pointers (not owned by the scene manager).
@@ -43,6 +47,7 @@ class UiSceneManager {
 
   bool web_vr_mode_ = false;
   bool secure_origin_ = false;
+  bool content_rendering_enabled_ = true;
 
   int next_available_id_ = 1;