Revert "Use focus ring for views button on all platforms"

This reverts commit f1e1cf79ce1aa12db141ed6f0060fc2db4322bb7.

Reason for revert: Appears to be causing lots of failures on linux-chromeos-dbg

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/linux-chromeos-dbg/10433

Original change's description:
> Use focus ring for views button on all platforms
> 
> On platforms other than Mac, ink drop highlight was used to indicate
> focus. This has some shortcomings such as possible low contrast,
> inconsistency across platforms or even across other UI components.
> This CL changes views button to use focus ring for keyboard focus
> on all platforms.
> 
> BUG=864642,924232
> 
> Change-Id: I31b3f2aa78259e6ae365bfde6687b92314e233e9
> Reviewed-on: https://chromium-review.googlesource.com/c/1429239
> Reviewed-by: Scott Violet <sky@chromium.org>
> Commit-Queue: Wei Li <weili@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#625459}

TBR=sky@chromium.org,weili@chromium.org

Change-Id: I7b288d364f768f225e803d9a2f50845ed7ab976e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 864642, 924232
Reviewed-on: https://chromium-review.googlesource.com/c/1433383
Reviewed-by: Timothy Loh <timloh@chromium.org>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625510}
5 files changed