Clean up WebVR RequestPresent and make callback asynchronous.

device/vr/android/gvr/gvr_device_provider.cc

 // Copyright 2016 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/android/gvr/gvr_device_provider.h"
 
 #include <jni.h>
 
 #include "base/android/context_utils.h"
 #include "base/android/jni_android.h"
@@ skipping 38 matching lines @@
       device::GvrDelegateProvider::GetInstance();
   if (!delegate_provider)
     return;
 
   if (!vr_device_) {
     vr_device_.reset(
         new GvrDevice(this, delegate_provider->GetNonPresentingDelegate()));
   }
 }
 
-bool GvrDeviceProvider::RequestPresent() {
+void GvrDeviceProvider::RequestPresent(
+    const base::Callback<void(bool)>& callback) {
   device::GvrDelegateProvider* delegate_provider =
       device::GvrDelegateProvider::GetInstance();
   if (!delegate_provider)
-    return false;
+    return callback.Run(false);
 
   // RequestWebVRPresent is async as a render thread may be created.
-  return delegate_provider->RequestWebVRPresent(weak_ptr_factory_.GetWeakPtr());
+  delegate_provider->RequestWebVRPresent(weak_ptr_factory_.GetWeakPtr(),
+                                         callback);
 }
 
 // VR presentation exit requested by the API.
 void GvrDeviceProvider::ExitPresent() {
   SwitchToNonPresentingDelegate();
   // If we're presenting currently stop.
   GvrDelegateProvider* delegate_provider = GvrDelegateProvider::GetInstance();
   if (delegate_provider)
     delegate_provider->ExitWebVRPresent();
 }
@@ skipping 34 matching lines @@
     return;
 
   vr_device_->SetDelegate(delegate_provider->GetNonPresentingDelegate());
 
   // Remove GVR gamepad polling.
   GamepadDataFetcherManager::GetInstance()->RemoveSourceFactory(
       GAMEPAD_SOURCE_GVR);
 }
 
 }  // namespace device