Implement a means of letting native VR Shell control the HTML UI.

chrome/browser/ui/webui/vr_shell/vr_shell_ui_message_handler.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_UI_WEBUI_VR_SHELL_VR_SHELL_UI_MESSAGE_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_VR_SHELL_VR_SHELL_UI_MESSAGE_HANDLER_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 namespace base {
 class ListValue;
 }
 
 namespace vr_shell {
 class VrShell;
 }
 
 class VrShellUIMessageHandler : public content::WebUIMessageHandler {
  public:
   VrShellUIMessageHandler();
   ~VrShellUIMessageHandler() override;
 
+  void SendCommandToUi(const base::Value& value);
+
  private:
   // content::WebUIMessageHandler:
   void RegisterMessages() override;
+  void OnJavascriptAllowed() override;
 
   void HandleDomLoaded(const base::ListValue* args);
   void HandleUpdateScene(const base::ListValue* args);
   void HandleDoAction(const base::ListValue* args);
 
   base::WeakPtr<vr_shell::VrShell> vr_shell_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellUIMessageHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_VR_SHELL_VR_SHELL_UI_MESSAGE_HANDLER_H_