Fix unresponsive tab closure when a navigation is in progress.

Fix unresponsive tab closure when a navigation is in progress.

TBR=nasko@chromium.org
BUG=420557
TEST=Close a tab with an infinite unload event, then navigate right away.

Committed: https://crrev.com/1e3617abe7bdb3dd2be95a88924859c640e6944b
Cr-Commit-Position: refs/heads/master@{#298987}

[Charlie Reis, 2014-10-09 20:39:41]

creis@chromium.org changed reviewers:
+ nasko@chromium.org

[Charlie Reis, 2014-10-09 20:39:41]

Nasko, can you take a look?  This prevents us from hitting the CHECK I added in
https://codereview.chromium.org/617273004, since IsWaitingForUnloadACK returns
true for close acks as well.

CC'ing Nick, since he and I were talking about http://crbug.com/418266.

[ncarter (slow), 2014-10-09 21:05:11]

nick@chromium.org changed reviewers:
+ nick@chromium.org

[ncarter (slow), 2014-10-09 21:05:11]

lgtm

[Charlie Reis, 2014-10-09 21:48:05]

Thanks!  Nasko's OOO today, so I'll TBR him.

[Charlie Reis, 2014-10-09 21:48:25]

The CQ bit was checked by creis@chromium.org

[commit-bot: I haz the power, 2014-10-09 21:50:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/633323003/1

[commit-bot: I haz the power, 2014-10-09 22:01:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-09 22:02:09]

Patchset 1 (id:??) landed as
https://crrev.com/1e3617abe7bdb3dd2be95a88924859c640e6944b
Cr-Commit-Position: refs/heads/master@{#298987}