[Mac][Material Design] Fix regression allowing chevron button dragging.

[Mac][Material Design] Fix regression allowing chevron button dragging.

A recent regression left the bookmarks bar's chevron button draggable
when it should not be.

R=avi@chromium.org
BUG=616412
Committed: https://crrev.com/29e90b8c7137c5e83a021a8453de434fc5968255
Cr-Commit-Position: refs/heads/master@{#397522}

[shrike, 2016-06-02 19:14:38]

PTAL

[Avi (use Gerrit), 2016-06-02 19:50:02]

lgtm

[shrike, 2016-06-02 20:20:31]

The CQ bit was checked by shrike@chromium.org

[commit-bot: I haz the power, 2016-06-02 20:21:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2035843003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2035843003/1

[commit-bot: I haz the power, 2016-06-02 21:58:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-02 22:00:07]

Description was changed from

==========
[Mac][Material Design] Fix regression allowing chevron button dragging.

A recent regression left the bookmarks bar's chevron button draggable
when it should not be.

R=avi@chromium.org
BUG=616412
==========

to

==========
[Mac][Material Design] Fix regression allowing chevron button dragging.

A recent regression left the bookmarks bar's chevron button draggable
when it should not be.

R=avi@chromium.org
BUG=616412

Committed: https://crrev.com/29e90b8c7137c5e83a021a8453de434fc5968255
Cr-Commit-Position: refs/heads/master@{#397522}
==========

[commit-bot: I haz the power, 2016-06-02 22:00:08]

Patchset 1 (id:??) landed as
https://crrev.com/29e90b8c7137c5e83a021a8453de434fc5968255
Cr-Commit-Position: refs/heads/master@{#397522}