perfetto-ui: Unify track and track group borders am: 975c1f07f1
perfetto-ui: Unify track and track group borders
am: 975c1f07f1

Change-Id: I99bd4d09047da679bfd8d13a80e3a9ae02d6595c

google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto