Adjust common theme tree colors.

Screenshots: https://bugs.chromium.org/p/chromium/issues/detail?id=1024091#c1

Bug: 1024091
Change-Id: Idb0cab8c8b446d65a74568e9ccd8de6182349782
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1913587
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714913}
1 file changed