Fix exiting WebVR via Android UI not fully exiting fullscreen.

device/vr/vr_device.cc

 // Copyright 2015 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.
 
 #include "device/vr/vr_device.h"
 #include "device/vr/vr_device_provider.h"
 #include "device/vr/vr_service_impl.h"
 
 namespace device {
 
@@ skipping 36 matching lines @@
   if (vr_device_info.is_null())
     return;
 
   for (const auto& display : displays_) {
     mojom::VRDisplayClient* client = display.second->client();
     if (client)
       client->OnDisplayChanged(vr_device_info.Clone());
   }
 }
 
-void VRDevice::OnExitPresent(VRServiceImpl* service) {
-  DisplayClientMap::iterator it = displays_.find(service);
+void VRDevice::OnExitPresent() {
+  DisplayClientMap::iterator it = displays_.find(presenting_service_);
   if (it != displays_.end()) {
     mojom::VRDisplayClient* client = it->second->client();
     if (client)
       client->OnExitPresent();
   }
+
+  presenting_service_ = nullptr;
 }
 
 }  // namespace device