commit 1d37839e54566033090fbb82f89dd1dba04c3621
author gangwu <gangwu@chromium.org> Tue May 02 01:13:36 2017
committer Commit bot <commit-bot@chromium.org> Tue May 02 01:13:36 2017
tree 76c62e6080e95202674f84d3c5fe84b323b0fa96
parent 95b984c544b0216c36a04231151a6509ac7240d5

[Sync] Sync types never recovers from throttle

Should check if SyncSchedulerImpl::OnTypesUnblocked need to be scheduled.

BUG=710644

blocked jobs are
SyncSchedulerImpl::Unthrottle
SyncSchedulerImpl::ExponentialBackoffRetry
SyncSchedulerImpl::OnTypesUnblocked

|pending_wakeup_timer_| is used to schedule blocked type jobs and
|PerformDelayedNudge|, and if OnTypesUnblocked is scheduled, but
|PerformDelayedNudge| or other blocked jobs got scheduled before
OnTypesUnblocked, OnTypesUnblocked will be replaced, and never been
scheduled again. so we should check if there are any type is blocked
after each of those jobs' run.

Review-Url: https://codereview.chromium.org/2828423002
Cr-Commit-Position: refs/heads/master@{#468522}