Implement WebVR presentation pausing for VR Shell Menu Mode

chrome/browser/android/vr_shell/vr_shell.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_VR_SHELL_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_H_
 
 #include <jni.h>
 
 #include <memory>
@@ skipping 103 matching lines @@
   void QueueTask(base::Callback<void()>& callback);
 
   // Perform a UI action triggered by the javascript API.
   void DoUiAction(const UiAction action);
 
  private:
   ~VrShell() override;
   void LoadUIContent();
   void DrawVrShell(const gvr::Mat4f& head_pose, gvr::Frame &frame);
   void DrawUiView(const gvr::Mat4f* head_pose,
-                  const std::vector<const ContentRectangle*>& elements);
+                  const std::vector<const ContentRectangle*>& elements,
+                  bool clear);
   void DrawElements(const gvr::Mat4f& render_matrix,
                     const std::vector<const ContentRectangle*>& elements);
   void DrawCursor(const gvr::Mat4f& render_matrix);
   void DrawWebVr();
 
   void UpdateController(const gvr::Vec3f& forward_vector);
 
   void HandleQueuedTasks();
 
   // content::WebContentsObserver implementation.
@@ skipping 56 matching lines @@
   base::WeakPtrFactory<VrShell> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShell);
 };
 
 bool RegisterVrShell(JNIEnv* env);
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_H_