Clean up WebVR RequestPresent and make callback asynchronous.

device/vr/vr_device.cc

Index: device/vr/vr_device.cc
diff --git a/device/vr/vr_device.cc b/device/vr/vr_device.cc
index 89c330452156e783b9b35aeb4519fb277736987a..78091044558e47db9ecb90ea30803c48fcf599ba 100644
--- a/device/vr/vr_device.cc
+++ b/device/vr/vr_device.cc
@@ -18,9 +18,11 @@ VRDevice::VRDevice() : presenting_service_(nullptr), id_(next_id_) {
 
 VRDevice::~VRDevice() {}
 
-bool VRDevice::RequestPresent(bool secure_origin) {
-  return true;
-};
+void VRDevice::RequestPresent(const base::Callback<void(bool)>& callback) {
+  callback.Run(true);
+}
+
+void VRDevice::SetSecureOrigin(bool secure_origin) {}
 
 void VRDevice::AddService(VRServiceImpl* service) {
   // Create a VRDisplayImpl for this service/device pair