Fix an issue that download progress notification is shown when killing browser

Fix an issue that download progress notification is shown when killing browser

When browser gets killed, we should show a paused notification.
However, onTaskRemoved() is often called too early before process fully
stops.
As a result, a progress notification can arrive after Chrome changes all the
notification to paused.
This may cause chrome to show a paused notification and then immediately
change it to progress while killing the browser.
Only progress notification matters, cancel/pause doesn't really matter.

BUG=642191
Committed: https://crrev.com/540399d5f34abfcae1828e2c36835ffae391e319
Cr-Commit-Position: refs/heads/master@{#415439}

[qinmin, 2016-08-30 19:30:40]

qinmin@chromium.org changed reviewers:
+ dfalcantara@chromium.org

[qinmin, 2016-08-30 19:30:41]

PTAL

[gone, 2016-08-30 20:11:45]

lgtm

[qinmin, 2016-08-30 20:39:28]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2016-08-30 20:40:14]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-30 21:43:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-30 21:45:51]

Description was changed from

==========
Fix an issue that download progress notification is shown when killing browser

When browser gets killed, we should show a paused notification.
However, onTaskRemoved() is often called too early before process fully
stops.
As a result, a progress notification can arrive after Chrome changes all the
notification to paused.
This may cause chrome to show a paused notification and then immediately
change it to progress while killing the browser.
Only progress notification matters, cancel/pause doesn't really matter.

BUG=642191
==========

to

==========
Fix an issue that download progress notification is shown when killing browser

When browser gets killed, we should show a paused notification.
However, onTaskRemoved() is often called too early before process fully
stops.
As a result, a progress notification can arrive after Chrome changes all the
notification to paused.
This may cause chrome to show a paused notification and then immediately
change it to progress while killing the browser.
Only progress notification matters, cancel/pause doesn't really matter.

BUG=642191

Committed: https://crrev.com/540399d5f34abfcae1828e2c36835ffae391e319
Cr-Commit-Position: refs/heads/master@{#415439}
==========

[commit-bot: I haz the power, 2016-08-30 21:45:52]

Patchset 1 (id:??) landed as
https://crrev.com/540399d5f34abfcae1828e2c36835ffae391e319
Cr-Commit-Position: refs/heads/master@{#415439}