Call UpdateControlButtonsVisibility() in OnMouseMoved().

Call UpdateControlButtonsVisibility() in OnMouseMoved().

This is workaround for the issue that OnMouseEntered() is sometimes
not called.

BUG=703717
Change-Id: I80d6c305f2577775cb7a7cb7d960013950a5d201
Reviewed-on: https://chromium-review.googlesource.com/516685
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>;
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>;
Cr-Commit-Position: refs/heads/master@{#475286}
(cherry picked from commit 680cdf421c7cf607910ae1608f75541e5f03281f)

Review-Url: https://codereview.chromium.org/2911983005 .
Cr-Commit-Position: refs/branch-heads/3071@{#719}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/0f7330516ee00830359f6d3f59fd585e8b1451ab

[yoshiki, 2017-05-30 05:09:48]

Description was changed from

==========
Call UpdateControlButtonsVisibility() in OnMouseMoved().

This is workaround for the issue that OnMouseEntered() is sometimes
not called.

BUG=703717

Change-Id: I80d6c305f2577775cb7a7cb7d960013950a5d201
Reviewed-on: https://chromium-review.googlesource.com/516685
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#475286}
(cherry picked from commit 680cdf421c7cf607910ae1608f75541e5f03281f)
==========

to

==========
Call UpdateControlButtonsVisibility() in OnMouseMoved().

This is workaround for the issue that OnMouseEntered() is sometimes
not called.

BUG=703717

Change-Id: I80d6c305f2577775cb7a7cb7d960013950a5d201
Reviewed-on: https://chromium-review.googlesource.com/516685
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#475286}
(cherry picked from commit 680cdf421c7cf607910ae1608f75541e5f03281f)

Review-Url: https://codereview.chromium.org/2911983005 .
Cr-Commit-Position: refs/branch-heads/3071@{#719}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/0f7330516ee00830359f6d3f59fd...
==========

[yoshiki, 2017-05-30 05:09:50]

Committed patchset #1 (id:1) manually as
0f7330516ee00830359f6d3f59fd585e8b1451ab.