Add way to get native VR UI information from Java

chrome/browser/android/vr_shell/ui_scene.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_SCENE_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_UI_SCENE_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 59 matching lines @@
   ContentRectangle* GetUiElementById(int element_id);
 
   std::vector<const ContentRectangle*> GetWorldElements() const;
   std::vector<const ContentRectangle*> GetHeadLockedElements() const;
   bool HasVisibleHeadLockedElements() const;
 
   const Colorf& GetBackgroundColor() const;
   float GetBackgroundDistance() const;
   bool GetWebVrRenderingEnabled() const;
 
+  std::unique_ptr<base::DictionaryValue> CreateUiElementInfo(int element_id);
+
  private:
   void ApplyRecursiveTransforms(const ContentRectangle& element,
                                 Transform* transform,
                                 float* opacity,
                                 bool* lock_to_fov);
   void ApplyDictToElement(const base::DictionaryValue& dict,
                           ContentRectangle* element);
 
   std::vector<std::unique_ptr<ContentRectangle>> ui_elements_;
   ContentRectangle* content_element_ = nullptr;
   Colorf background_color_ = {0.1f, 0.1f, 0.1f, 1.0f};
   float background_distance_ = 10.0f;
   bool webvr_rendering_enabled_ = true;
 
   DISALLOW_COPY_AND_ASSIGN(UiScene);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_SCENE_H_