Implement WebVR presentation pausing for VR Shell Menu Mode

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 252aa117667e09cce9ca7041c791706dc8c2a220..a24a68c1629b9946ec36f5f2db20701d17b95ab2 100644
--- a/device/vr/android/gvr/gvr_device_provider.cc
+++ b/device/vr/android/gvr/gvr_device_provider.cc
@@ -107,6 +107,28 @@ void GvrDeviceProvider::OnGvrDelegateRemoved() {
   ExitPresent();
 }
 
+void GvrDeviceProvider::OnDisplayBlur() {
+  if (!main_thread_task_runner_->BelongsToCurrentThread()) {
+    main_thread_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&GvrDeviceProvider::OnDisplayBlur, base::Unretained(this)));
+    return;
+  }
+  if (client_)
+    client_->OnDisplayBlur(vr_device_.get());
+}
+
+void GvrDeviceProvider::OnDisplayFocus() {
+  if (!main_thread_task_runner_->BelongsToCurrentThread()) {
+    main_thread_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&GvrDeviceProvider::OnDisplayFocus, base::Unretained(this)));
+    return;
+  }
+  if (client_)
+    client_->OnDisplayFocus(vr_device_.get());
+}
+
 void GvrDeviceProvider::GvrDelegateReady(GvrDelegate* delegate) {
   DCHECK(main_thread_task_runner_->BelongsToCurrentThread());