Add support of vrdisplayconnect and vrdisplaydisconnect event

device/vr/android/gvr/gvr_device_provider.cc

Index: device/vr/android/gvr/gvr_device_provider.cc
diff --git a/device/vr/android/gvr/gvr_device_provider.cc b/device/vr/android/gvr/gvr_device_provider.cc
index ad21151426db9f44117c538c14586b8f061e47e8..21e0790beeb9c063a85db16b7a8d2d7099d899e9 100644
--- a/device/vr/android/gvr/gvr_device_provider.cc
+++ b/device/vr/android/gvr/gvr_device_provider.cc
@@ -95,12 +95,20 @@ void GvrDeviceProvider::OnDelegateInitialized(GvrDelegate* delegate) {
   if (!vr_device_)
     vr_device_.reset(new GvrDevice(this, delegate));
 
-  // Should fire a vrdisplayconnected event here.
+  if (vr_device_)
+    vr_device_->UpdateConnectionStatus(true);
 }
 
 void GvrDeviceProvider::OnDelegateShutdown() {
   // Nothing to do here just yet. Eventually want to shut down the VRDevice and
   // fire a vrdisplaydisconnected event.
+  if (vr_device_)
+    vr_device_->UpdateConnectionStatus(false);
+}
+
+void GvrDeviceProvider::PollEvents(VRClientDispatcher* client) {
+  if (vr_device_)
+    vr_device_->PollEvents(client);
 }
 
 }  // namespace device