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

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

Index: ui/ozone/platform/drm/gpu/hardware_display_plane_manager.cc
diff --git a/ui/ozone/platform/drm/gpu/hardware_display_plane_manager.cc b/ui/ozone/platform/drm/gpu/hardware_display_plane_manager.cc
index ba915564cad59f33fc729f13859b8fdabd0a9b0e..37ce65322b7dc556dac3fba6c72751674386ca68 100644
--- a/ui/ozone/platform/drm/gpu/hardware_display_plane_manager.cc
+++ b/ui/ozone/platform/drm/gpu/hardware_display_plane_manager.cc
@@ -36,6 +36,9 @@ HardwareDisplayPlaneList::PageFlipInfo::PageFlipInfo(uint32_t crtc_id,
     : crtc_id(crtc_id), framebuffer(framebuffer), crtc(crtc) {
 }
 
+HardwareDisplayPlaneList::PageFlipInfo::PageFlipInfo(
+    const PageFlipInfo& other) = default;
+
 HardwareDisplayPlaneList::PageFlipInfo::~PageFlipInfo() {
 }