Implement WebVR presentation pausing for VR Shell Menu Mode

chrome/browser/android/vr_shell/ui_interface.h

Index: chrome/browser/android/vr_shell/ui_interface.h
diff --git a/chrome/browser/android/vr_shell/ui_interface.h b/chrome/browser/android/vr_shell/ui_interface.h
index 315c013f2a6d81fc7969da3ba65fdaa087b7682e..ae8f00e38b5a58c47191febaf64f514790573e2c 100644
--- a/chrome/browser/android/vr_shell/ui_interface.h
+++ b/chrome/browser/android/vr_shell/ui_interface.h
@@ -22,12 +22,14 @@ class UiInterface {
   enum Mode {
     STANDARD,
     WEB_VR,
+    MENU,
   };
 
   UiInterface();
   virtual ~UiInterface();
 
   void SetMode(Mode mode);
+  Mode GetMode() { return mode_; }
   void SetSecureOrigin(bool secure);
 
   // Called by WebUI when starting VR.
@@ -37,6 +39,7 @@ class UiInterface {
  private:
   void FlushUpdates();
 
+  Mode mode_;
   UiCommandHandler* handler_;
   bool loaded_ = false;
   base::DictionaryValue updates_;