Switch DRM platform to using a separate thread

ui/ozone/platform/drm/gpu/drm_window.cc

Index: ui/ozone/platform/drm/gpu/drm_window.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_window.cc b/ui/ozone/platform/drm/gpu/drm_window.cc
index ebf937dbfdebdafdfe4b9ab5c2b243b1828430c2..9137fc8f1c971c5b06262d7b2a7322fa8771c731 100644
--- a/ui/ozone/platform/drm/gpu/drm_window.cc
+++ b/ui/ozone/platform/drm/gpu/drm_window.cc
@@ -78,6 +78,10 @@ HardwareDisplayController* DrmWindow::GetController() {
   return controller_;
 }
 
+scoped_refptr<DrmDevice> DrmWindow::GetAllocationDrmDevice() const {
+  return device_manager_->GetDrmDevice(widget_);
+}
+
 void DrmWindow::OnBoundsChanged(const gfx::Rect& bounds) {
   TRACE_EVENT2("drm", "DrmWindow::OnBoundsChanged", "widget", widget_, "bounds",
                bounds.ToString());
@@ -125,19 +129,18 @@ void DrmWindow::QueueOverlayPlane(const OverlayPlane& plane) {
   pending_planes_.push_back(plane);
 }
 
-bool DrmWindow::SchedulePageFlip(bool is_sync,
+void DrmWindow::SchedulePageFlip(bool is_sync,
                                  const SwapCompletionCallback& callback) {
   last_submitted_planes_.clear();
   last_submitted_planes_.swap(pending_planes_);
   last_swap_sync_ = is_sync;
 
   if (controller_) {
-    return controller_->SchedulePageFlip(last_submitted_planes_, is_sync, false,
-                                         callback);
+    controller_->SchedulePageFlip(last_submitted_planes_, is_sync, false,
+                                  callback);
+  } else {
+    callback.Run(gfx::SwapResult::SWAP_ACK);
   }
-
-  callback.Run(gfx::SwapResult::SWAP_ACK);
-  return true;
 }
 
 bool DrmWindow::TestPageFlip(const std::vector<OverlayCheck_Params>& overlays,
@@ -194,6 +197,17 @@ void DrmWindow::GetVSyncParameters(
   callback.Run(timebase, interval);
 }
 
+bool DrmWindow::IsDisplayedOnUniversalDisplayLinkDevice() const {
+  if (!controller_)
+    return false;
+
+  scoped_refptr<DrmDevice> primary =
+      device_manager_->GetDrmDevice(gfx::kNullAcceleratedWidget);
+  DCHECK(primary);
+
+  return primary != controller_->GetAllocationDrmDevice();
+}
+
 void DrmWindow::ResetCursor(bool bitmap_only) {
   if (!controller_)
     return;