Fix crash when destory VRServiceImpl

device/vr/vr_service_impl.cc

Index: device/vr/vr_service_impl.cc
diff --git a/device/vr/vr_service_impl.cc b/device/vr/vr_service_impl.cc
index f80037060840dcd2fe3e24e3633c93e4f5fbecc0..9d0fb36618c53e59443d23faf2597e3da3f59b4d 100644
--- a/device/vr/vr_service_impl.cc
+++ b/device/vr/vr_service_impl.cc
@@ -17,6 +17,10 @@ namespace device {
 VRServiceImpl::VRServiceImpl() : listening_for_activate_(false) {}
 
 VRServiceImpl::~VRServiceImpl() {
+  // Destroy VRDisplay before calling RemoveService below. RemoveService might
+  // implicitly trigger destory VRDevice which VRDisplay needs to access in its
+  // dtor.
+  displays_.clear();
   VRDeviceManager::GetInstance()->RemoveService(this);
 }