Expose Gamepad API instance for Cardboard button

chrome/browser/android/vr_shell/vr_shell_gl.h

Index: chrome/browser/android/vr_shell/vr_shell_gl.h
diff --git a/chrome/browser/android/vr_shell/vr_shell_gl.h b/chrome/browser/android/vr_shell/vr_shell_gl.h
index df5d8a107200cfd8e30923f76fd5926eb73e24c3..39cb3efb893fd742022d248ed21a28285af0d24a 100644
--- a/chrome/browser/android/vr_shell/vr_shell_gl.h
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.h
@@ -78,7 +78,7 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   void Initialize();
   void InitializeGl(gfx::AcceleratedWidget window);
 
-  void OnTriggerEvent();
+  void OnTriggerEvent(bool touched);
   void OnPause();
   void OnResume();
 
@@ -191,6 +191,7 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   std::unique_ptr<VrShellRenderer> vr_shell_renderer_;
 
   bool touch_pending_ = false;
+  bool currently_touched_ = false;
   vr::Quatf controller_quat_;
 
   gfx::Point3F target_point_;