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

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

Index: ui/ozone/platform/drm/gpu/fake_plane_info.cc
diff --git a/ui/ozone/platform/drm/gpu/fake_plane_info.cc b/ui/ozone/platform/drm/gpu/fake_plane_info.cc
index 3695383e53e7ccdfeb9bd1cff2fa4f681387f15a..2e9a2a732d858497138bd9687bf58d6d4736f60d 100644
--- a/ui/ozone/platform/drm/gpu/fake_plane_info.cc
+++ b/ui/ozone/platform/drm/gpu/fake_plane_info.cc
@@ -18,6 +18,8 @@ FakePlaneInfo::FakePlaneInfo(uint32_t plane_id,
                              const std::vector<uint32_t>& formats)
     : id(plane_id), allowed_crtc_mask(crtc_mask), allowed_formats(formats) {}
 
+FakePlaneInfo::FakePlaneInfo(const FakePlaneInfo& other) = default;
+
 FakePlaneInfo::~FakePlaneInfo() {}
 
 }  // namespace ui