Disable region copy on ARM since it isn't supported

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

Index: ui/ozone/platform/drm/gpu/drm_surface.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_surface.cc b/ui/ozone/platform/drm/gpu/drm_surface.cc
index f55c925d34780cdcbe077a85fb28aa296c4d1a9a..dc9fbf53a8c124cc450ddfaba267c17ae4206ef3 100644
--- a/ui/ozone/platform/drm/gpu/drm_surface.cc
+++ b/ui/ozone/platform/drm/gpu/drm_surface.cc
@@ -99,9 +99,14 @@ void DrmSurface::SchedulePageFlip() {
 
   // Update our front buffer pointer.
   std::swap(front_buffer_, back_buffer_);
-  pending_pageflip_ = window_->SchedulePageFlip(
-      false /* is_sync */,
-      base::Bind(&DrmSurface::OnPageFlip, weak_ptr_factory_.GetWeakPtr()));
+  // First set the pending flag otherwise there could be a re-entrancy issue if
+  // the callback is executed synchronously.
+  pending_pageflip_ = true;
+  if (!window_->SchedulePageFlip(false /* is_sync */,
+                                 base::Bind(&DrmSurface::OnPageFlip,
+                                            weak_ptr_factory_.GetWeakPtr()))) {
+    pending_pageflip_ = false;
+  }
 }
 
 void DrmSurface::OnPageFlip(gfx::SwapResult result) {