ui: Add out-of-line copy ctors for complex classes.

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

Index: ui/ozone/platform/drm/gpu/overlay_plane.cc
diff --git a/ui/ozone/platform/drm/gpu/overlay_plane.cc b/ui/ozone/platform/drm/gpu/overlay_plane.cc
index c883eb00aa333468342c728fa6c164d40f0933e0..d7016701cd233b6792727d895a95014b4c02892e 100644
--- a/ui/ozone/platform/drm/gpu/overlay_plane.cc
+++ b/ui/ozone/platform/drm/gpu/overlay_plane.cc
@@ -27,6 +27,8 @@ OverlayPlane::OverlayPlane(const scoped_refptr<ScanoutBuffer>& buffer,
       display_bounds(display_bounds),
       crop_rect(crop_rect) {}
 
+OverlayPlane::OverlayPlane(const OverlayPlane& other) = default;
+
 OverlayPlane::~OverlayPlane() {
 }