Send vrdisplayactivate to the most recently focused navigator listening for displayactivate.

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 9b5be90ee8c1d6eeca3e479436fb6969fa93ed18..46a2f01b49d6171586fa9a1aa4c39359548c3f0c 100644
--- a/device/vr/android/gvr/gvr_device_provider.cc
+++ b/device/vr/android/gvr/gvr_device_provider.cc
@@ -44,10 +44,6 @@ device::GvrDelegateProvider* GvrDeviceProvider::GetDelegateProvider() {
 }
 
 void GvrDeviceProvider::Initialize() {
-  // TODO(mthiesse): Clean up how we connect the GvrDelegateProvider to the
-  // GvrDeviceProvider so we don't have to call this function multiple times.
-  // Ideally the DelegateProvider would always be available, and GetInstance()
-  // would create it.
   Initialize(device::GvrDelegateProvider::GetInstance());
 }