Revert "Fix inconsistent hosted app title bar text color readability algorithm"

This reverts commit 9c6ad3095f59d1378e785eb7c4289bf2c6edadd3.

Reason for revert: Tests added in this CL are failing on mac-cocoa-rel
 since landing.

Original change's description:
> Fix inconsistent hosted app title bar text color readability algorithm
> 
> This CL updates the title text color for Linux and Windows 7 hosted
> app windows to be more consistent with Windows 10, Chrome OS, Android
> and text colors used by Gmail and Inbox.
> 
> Before: https://bugs.chromium.org/p/chromium/issues/attachment?aid=357634&signed_aid=ONM068fpCagoCFdrDrfYuw==&inline=1
> After: https://bugs.chromium.org/p/chromium/issues/attachment?aid=357642&signed_aid=2gnT0P6z9_fNMEZAGLKLnw==&inline=1
> See bug for more screenshots.
> 
> Bug: 883177
> Change-Id: Ic24e1cf0b445251ebfdcd1aa0ae74c9343b1ff8e
> Reviewed-on: https://chromium-review.googlesource.com/1218186
> Commit-Queue: Alan Cutter <alancutter@chromium.org>
> Reviewed-by: James Cook <jamescook@chromium.org>
> Reviewed-by: Michael Wasserman <msw@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#591279}

TBR=jamescook@chromium.org,msw@chromium.org,alancutter@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 883177
Bug: 885164
Change-Id: I22a52611a5478ee1d430ccd8ca1a507f7237d4f7
Reviewed-on: https://chromium-review.googlesource.com/1230435
Reviewed-by: Asanka Herath <asanka@chromium.org>
Commit-Queue: Asanka Herath <asanka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592069}
8 files changed