Use Android style title bar colors for theme colors on chromeOS

This CL updates the way hosted app windows pick title bar colors
while a theme color is set on chromeOS.

This aligns the behaviour with Android, see:
https://codereview.chromium.org/1956803002.

Before:
https://bugs.chromium.org/p/chromium/issues/attachment?aid=329991&signed_aid=3q0FM93vRJrPJV7kMinOTw==&inline=1
https://bugs.chromium.org/p/chromium/issues/attachment?aid=333012&signed_aid=VNXQQhjxyzYYyg36S3nnOQ==&inline=1
https://bugs.chromium.org/p/chromium/issues/attachment?aid=330203&signed_aid=DoC1IRqCuP659D2dMoL1_Q==&inline=1

After:
https://bugs.chromium.org/p/chromium/issues/attachment?aid=333244&signed_aid=J5yNTnY4-7RqGeYu32N8OA==&inline=1
https://bugs.chromium.org/p/chromium/issues/attachment?aid=333245&signed_aid=VOf6afQMQJbCApYu21wmyw==&inline=1
https://bugs.chromium.org/p/chromium/issues/attachment?aid=333257&signed_aid=OJzGQyVnXzCfXF6bZ16TCg==&inline=1
https://bugs.chromium.org/p/chromium/issues/attachment?aid=333258&signed_aid=jygsmXqxXfoPsPZXb_gqfg==&inline=1

Bug: 814121
Change-Id: I10a2e837d0c8a938072171715119a04c28e4f36a
Reviewed-on: https://chromium-review.googlesource.com/999213
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550045}
14 files changed