ozone-mus: Fix detecting displays on device in mustash.

ui/ozone/platform/drm/mus_thread_proxy.cc

Index: ui/ozone/platform/drm/mus_thread_proxy.cc
diff --git a/ui/ozone/platform/drm/mus_thread_proxy.cc b/ui/ozone/platform/drm/mus_thread_proxy.cc
index c70850aea21525270c4bde41976abc6cd6bde1fd..bbd717a0fd8acad8531d11913a9c0daeec300a80 100644
--- a/ui/ozone/platform/drm/mus_thread_proxy.cc
+++ b/ui/ozone/platform/drm/mus_thread_proxy.cc
@@ -74,16 +74,20 @@ void MusThreadProxy::DispatchObserversFromDrmThread() {
 
 void MusThreadProxy::RunObservers() {
   DCHECK(on_window_server_thread_.CalledOnValidThread());
-  for (GpuThreadObserver& observer : gpu_thread_observers_)
+  for (GpuThreadObserver& observer : gpu_thread_observers_) {
+    observer.OnGpuProcessLaunched();

[rjkroege, 2016/11/22 17:53:32]

This will obviously be not quite right when we support mojo ozone split-process
mode. Can you add a TODO here before landing reminding someone (probably me) to
do the right thing.

[sadrul, 2016/11/22 18:56:55]

Added TODO

     observer.OnGpuThreadReady();
+  }
 }
 
 void MusThreadProxy::AddGpuThreadObserver(GpuThreadObserver* observer) {
   DCHECK(on_window_server_thread_.CalledOnValidThread());
 
   gpu_thread_observers_.AddObserver(observer);
-  if (IsConnected())
+  if (IsConnected()) {
+    observer->OnGpuProcessLaunched();
     observer->OnGpuThreadReady();
+  }
 }
 
 void MusThreadProxy::RemoveGpuThreadObserver(GpuThreadObserver* observer) {