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..f0f55a536803a2140109c12c7dc3c515f179d809 100644
--- a/device/vr/android/gvr/gvr_device_provider.cc
+++ b/device/vr/android/gvr/gvr_device_provider.cc
@@ -62,6 +62,7 @@ void GvrDeviceProvider::Initialize() {
 }
 
 bool GvrDeviceProvider::RequestPresent() {
+  DCHECK(main_thread_task_runner_->BelongsToCurrentThread());
   device::GvrDelegateProvider* delegate_provider =
       device::GvrDelegateProvider::GetInstance();
   if (!delegate_provider)
@@ -95,9 +96,8 @@ void GvrDeviceProvider::ExitPresent() {
 
 void GvrDeviceProvider::OnGvrDelegateReady(GvrDelegate* delegate) {
   main_thread_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&GvrDeviceProvider::GvrDelegateReady, base::Unretained(this),
-                 base::Unretained(delegate)));
+      FROM_HERE, base::Bind(&GvrDeviceProvider::GvrDelegateReady, this,
+                            base::Unretained(delegate)));
 }
 
 void GvrDeviceProvider::OnGvrDelegateRemoved() {
@@ -107,6 +107,26 @@ void GvrDeviceProvider::OnGvrDelegateRemoved() {
   ExitPresent();
 }
 
+void GvrDeviceProvider::OnDisplayBlur() {
+  if (!main_thread_task_runner_->BelongsToCurrentThread()) {
+    main_thread_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&GvrDeviceProvider::OnDisplayBlur, 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, this));
+    return;
+  }
+  if (client_)
+    client_->OnDisplayFocus(vr_device_.get());
+}
+
 void GvrDeviceProvider::GvrDelegateReady(GvrDelegate* delegate) {
   DCHECK(main_thread_task_runner_->BelongsToCurrentThread());