Fix build break when building with enable_openvr=true on Windows

device/vr/openvr/openvr_device.h

 // Copyright 2017 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 DEVICE_VR_OPENVR_DEVICE_H
 #define DEVICE_VR_OPENVR_DEVICE_H
 
 #include "base/macros.h"
 #include "base/threading/simple_thread.h"
 #include "device/vr/vr_device.h"
@@ skipping 41 matching lines @@
 
     void UnregisterPollingEventCallback();
 
     void Bind(mojom::VRVSyncProviderRequest request);
 
     mojom::VRPosePtr getPose();
 
    private:
     void Run() override;
 
-    void GetVSync(const device::mojom::VRVSyncProvider::GetVSyncCallback&
-                      callback) override;
+    void GetVSync(
+        device::mojom::VRVSyncProvider::GetVSyncCallback callback) override;
 
     scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
     base::Callback<void()> on_polling_events_;
     vr::IVRSystem* vr_system_;
     mojo::Binding<device::mojom::VRVSyncProvider> binding_;
   };
 
   std::unique_ptr<OpenVRRenderLoop>
       render_loop_;  // TODO (BillOrr): This should not be a unique_ptr because
                      // the render_loop_ binds to VRVSyncProvider requests,
                      // so its lifetime should be tied to the lifetime of that
                      // binding.
 
   mojom::VRSubmitFrameClientPtr submit_client_;
 
   vr::IVRSystem* vr_system_;
 
   bool is_polling_events_;
 
   base::WeakPtrFactory<OpenVRDevice> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OpenVRDevice);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_VR_OPENVR_DEVICE_H