Revert of Disable ExternalPopupMenuRemoveTest.RemoveOnChange. (patchset #1 id:1 of https://codereview.chromium.org/1271223002/ )
Revert of Disable ExternalPopupMenuRemoveTest.RemoveOnChange. (patchset #1 id:1 of https://codereview.chromium.org/1271223002/ )

Reason for revert:
Reverted Blink r200000.

Original issue's description:
> Disable ExternalPopupMenuRemoveTest.RemoveOnChange.
>
> The behavior was intentionally changed by Blink r200000 [1].
>
> [1] https://src.chromium.org/viewvc/blink?revision=200000&view=revision
>
> BUG=516945
> TBR=keishi@chromium.org,avi@chromium.org
> NOTRY=true
>
> Committed: https://crrev.com/372de78e05c538ae724563ee107e47fbd17498d4
> Cr-Commit-Position: refs/heads/master@{#341867}

TBR=keishi@chromium.org,avi@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=516945

Review URL: https://codereview.chromium.org/1274813005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#341991}

Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,axinging/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Chilledheart/chromium,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,Chilledheart/chromium,Chilledheart/chromium,Chilledheart/chromium,axinging/chromium-crosswalk