Don't call AnimateClearingOneNotification if clearing all is already started.

Don't call AnimateClearingOneNotification if clearing all is already started.

AnimateClearingOneNotification calls itself recursively with delay
until all notifications to be cleared are removed from the list.
Calling AnimateClearingOneNotification by another reason while in
the delay causes calling front() on the empty std::list.

BUG=712162
Review-Url: https://codereview.chromium.org/2826003002
Cr-Commit-Position: refs/heads/master@{#465525}
(cherry picked from commit 3408db33fff22d04e05f38c875258debb25967f5)

Review-Url: https://codereview.chromium.org/2836273002 .
Cr-Commit-Position: refs/branch-heads/3029@{#770}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/7a492c8eed94ad223324dc033281f31b384bb200

[yhanada, 2017-04-25 04:59:02]

Description was changed from

==========
Don't call AnimateClearingOneNotification if clearing all is already started.

AnimateClearingOneNotification calls itself recursively with delay
until all notifications to be cleared are removed from the list.
Calling AnimateClearingOneNotification by another reason while in
the delay causes calling front() on the empty std::list.

BUG=712162

Review-Url: https://codereview.chromium.org/2826003002
Cr-Commit-Position: refs/heads/master@{#465525}
(cherry picked from commit 3408db33fff22d04e05f38c875258debb25967f5)
==========

to

==========
Don't call AnimateClearingOneNotification if clearing all is already started.

AnimateClearingOneNotification calls itself recursively with delay
until all notifications to be cleared are removed from the list.
Calling AnimateClearingOneNotification by another reason while in
the delay causes calling front() on the empty std::list.

BUG=712162

Review-Url: https://codereview.chromium.org/2826003002
Cr-Commit-Position: refs/heads/master@{#465525}
(cherry picked from commit 3408db33fff22d04e05f38c875258debb25967f5)

Review-Url: https://codereview.chromium.org/2836273002 .
Cr-Commit-Position: refs/branch-heads/3029@{#770}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/7a492c8eed94ad223324dc033281...
==========

[yhanada, 2017-04-25 04:59:04]

Committed patchset #1 (id:1) manually as
7a492c8eed94ad223324dc033281f31b384bb200 (tree was closed).