Tie VR omnibox to page load progress through TabObserver.

chrome/browser/android/vr_shell/ui_interface.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_INTERFACE_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_INTERFACE_H_
 
 #include "base/macros.h"
 #include "base/values.h"
 
@@ skipping 20 matching lines @@
 
   void SetMode(Mode mode);
   Mode GetMode() { return mode_; }
   void SetMenuMode(bool enabled);
   bool GetMenuMode() { return menu_mode_; }
   void SetFullscreen(bool enabled);
   bool GetFullscreen() { return fullscreen_; }
   void SetSecurityLevel(int level);
   void SetWebVRSecureOrigin(bool secure);
   void SetLoading(bool loading);
+  void SetLoadProgress(double progress);
   void SetURL(const GURL& url);
 
   // Called by WebUI when starting VR.
   void OnDomContentsLoaded();
   void SetUiCommandHandler(UiCommandHandler* handler);
 
  private:
   void FlushUpdates();
   void FlushModeState();
 
   Mode mode_;
   bool menu_mode_ = false;
   bool fullscreen_ = false;
   UiCommandHandler* handler_;
   bool loaded_ = false;
   base::DictionaryValue updates_;
 
   DISALLOW_COPY_AND_ASSIGN(UiInterface);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_INTERFACE_H_