Fix the DCHECK failure when starting and stopping GCMClient immediately

Fix the DCHECK failure when starting and stopping GCMClient immediately

BUG=383561
TEST=new test added

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=277072

[Nicolas Zea, 2014-06-11 21:16:23]

What happens if the task has already been posted to the GCMClient but hasn't run
yet? Can't it still trigger a DCHECK? It seems to me it's the GCMClient that
should be protecting itself

[jianli, 2014-06-11 21:36:14]

On 2014/06/11 21:16:23, Nicolas Zea wrote:
> What happens if the task has already been posted to the GCMClient but hasn't
run
> yet? Can't it still trigger a DCHECK? It seems to me it's the GCMClient that
> should be protecting itself

You're right. We should protect GCMClient. However, we also need to protect
GCMStore since otherwise app_message_counts_ might be messed up.

[Nicolas Zea, 2014-06-13 17:49:01]

lgtm

[jianli, 2014-06-13 18:03:06]

The CQ bit was checked by jianli@chromium.org

[commit-bot: I haz the power, 2014-06-13 18:04:10]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jianli@chromium.org/327263003/20001

[commit-bot: I haz the power, 2014-06-13 19:38:56]

Change committed as 277072