Expose Gamepad API instance for Cardboard button

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 200 matching lines @@
   // Current sizes for the render buffers.
   gfx::Size render_size_primary_;
   gfx::Size render_size_headlocked_;
 
   // Intended render_size_primary_ for use by VrShell, so that it
   // can be restored after exiting WebVR mode.
   gfx::Size render_size_vrshell_;
 
   std::unique_ptr<VrShellRenderer> vr_shell_renderer_;
 
+  bool cardboard_ = false;
   bool touch_pending_ = false;
   vr::Quatf controller_quat_;
 
   gfx::Point3F target_point_;
 
   // TODO(mthiesse): We need to handle elements being removed, and update this
   // state appropriately.
   UiElement* reticle_render_target_ = nullptr;
   UiElement* hover_target_ = nullptr;
   // TODO(mthiesse): We shouldn't have a fling target. Elements should fling
@@ skipping 44 matching lines @@
   gfx::Point3F pointer_start_;
 
   base::WeakPtrFactory<VrShellGl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellGl);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_GL_H_