drm_hwcomposer: Remove threading

Since HWC2 doesn't require the use of threads to implement correct
synchronization, remove some of these threads.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Robert Foss <robert.foss@collabora.com>
diff --git a/drmdisplaycomposition.h b/drmdisplaycomposition.h
index 470bf7e..9183925 100644
--- a/drmdisplaycomposition.h
+++ b/drmdisplaycomposition.h
@@ -42,6 +42,16 @@
   DRM_COMPOSITION_TYPE_MODESET,
 };
 
+struct DrmCompositionDisplayLayersMap {
+  int display;
+  bool geometry_changed = true;
+  std::vector<DrmHwcLayer> layers;
+
+  DrmCompositionDisplayLayersMap() = default;
+  DrmCompositionDisplayLayersMap(DrmCompositionDisplayLayersMap &&rhs) =
+      default;
+};
+
 struct DrmCompositionRegion {
   DrmHwcRect<int> frame;
   std::vector<size_t> source_layers;