Reason for revert:
All linux perf bots red, failing on various blink_perf tests. Speculatively reverting this CL since several bisects pointed to it.
BUG=485590
Original issue's description:
> Linux Aura accessibility is enabled only on GNOME desktops
>
> Linux Aura accessibility is not enabled on desktops different than GNOME2.
> GNOME3 has deprecated gconf in favor of gsettings and dconf.
> AT-SPI (cross-platform framework that provides communication between AT
> and application) bus launcher has a property called org.a11y.Bus.IsEnabled
> that could be easily read by dbus call.
>
> In generall this patch adds an additional check to enable accessibility.
> When gconf is available use gnome's accessibility key otherwise
> org.a11y.Bus.IsEnabled property.
>
> BUG=472183,468989,468112
> TBR=stevenjb@chromium.org,jochen@chromium.org
>
> Committed: https://crrev.com/16e2d5a386e3ddd5be818a0d27610b1e9ee9c08e
> Cr-Commit-Position: refs/heads/master@{#328651}
TBR=dmazzoni@chromium.org,plundblad@chromium.org,l.gombos@samsung.com,jochen@chromium.org,stevenjb@chromium.org,dpranke@chromium.org,k.czech@samsung.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=472183,468989,468112
Review URL: https://codereview.chromium.org/1124173005
Cr-Original-Commit-Position: refs/heads/master@{#329404}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c7c15e712cb77a0fe276166996b2bb787490c896
b12b3ab9e5