[vr] Add a frame rate counter for the vr UI

chrome/browser/android/vr_shell/vr_shell_gl.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_GL_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_GL_H_
 
 #include <memory>
 #include <queue>
 #include <utility>
@@ skipping 12 matching lines @@
 #include "ui/gfx/native_widget_types.h"
 
 namespace base {
 class ListValue;
 }
 
 namespace blink {
 class WebInputEvent;
 }
 
+namespace cc {
+class FrameRateCounter;
+}
+
 namespace gl {
 class GLContext;
 class GLSurface;
 class ScopedJavaSurface;
 class SurfaceTexture;
 }
 
 namespace gpu {
 struct MailboxHolder;
 }
@@ skipping 189 matching lines @@
   base::WeakPtr<VrShell> weak_vr_shell_;
   scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
 
   uint8_t frame_index_ = 0;
   // Larger than frame_index_ so it can be initialized out-of-band.
   uint16_t last_frame_index_ = -1;
 
   // Attributes for gesture detection while holding app button.
   gvr::Vec3f controller_start_direction_;
 
+  std::unique_ptr<cc::FrameRateCounter> frame_rate_counter_;
+
   base::WeakPtrFactory<VrShellGl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellGl);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_GL_H_