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 17dbec9f84acba6edcf93c9f8d6fdcbfacd4b263..7088976399be313f28f1d81715f6a5ae9ad00766 100644
--- a/chrome/browser/android/vr_shell/vr_shell_gl.h
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.h
@@ -74,7 +74,7 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   void Initialize();
   void InitializeGl(gfx::AcceleratedWidget window);
 
-  void OnTriggerEvent();
+  void OnTriggerEvent(bool touched);
   void OnPause();
   void OnResume();
 
@@ -219,6 +219,7 @@ 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_;