Add support to send optimal format as part of ScheduleOverlayPlane

ui/ozone/platform/drm/host/drm_overlay_candidates_host.cc

Index: ui/ozone/platform/drm/host/drm_overlay_candidates_host.cc
diff --git a/ui/ozone/platform/drm/host/drm_overlay_candidates_host.cc b/ui/ozone/platform/drm/host/drm_overlay_candidates_host.cc
index 1397d7ddd9c9e0b4711b8b4d8b3ea15f11c6c698..f8c7de5166a0960fde1717f5a27d499f0424090e 100644
--- a/ui/ozone/platform/drm/host/drm_overlay_candidates_host.cc
+++ b/ui/ozone/platform/drm/host/drm_overlay_candidates_host.cc
@@ -15,6 +15,8 @@ namespace ui {
 
 namespace {
 const size_t kMaxCacheSize = 100;
+// Optimal format for rendering on overlay.
+const gfx::BufferFormat kOverlayRenderFormat = gfx::BufferFormat::UYVY_422;
 }  // namespace
 
 bool DrmOverlayCandidatesHost::OverlayCompare::operator()(
@@ -81,6 +83,13 @@ void DrmOverlayCandidatesHost::CheckOverlaySupport(
           in_use_compatible_params_.find(lookup);
       if (last_iter != in_use_compatible_params_.end()) {
         candidate.overlay_handled = last_iter->second;
+        // TODO(kalyank): Figure out the optimal render format for overlay. We
+        // should get this from GPU process side. See http://crbug.com/553264.
+        if (candidate.plane_z_order > 0) {
+          candidate.format = kOverlayRenderFormat;
+          candidate.handle_scaling = true;
+        }
+
         compatible_candidates++;
         if (candidate.overlay_handled)
           planes_in_use++;