Fix TestingPlatformSupportWithMockScheduler::runForPeriodSeconds

Fix TestingPlatformSupportWithMockScheduler::runForPeriodSeconds

When one calls runForPeriodSeconds(x) you naturally expect the
testing clock to alwats advance by that many seconds.

Unfortunately cc::OrderedSimpleTaskRunner is a strange beast and
the actual time advances to the last delayed task before the
deadline if any.

This patch fixes that and makes the operation of timer fast
forwarding explicit.  It also fixes a bug in
TimerTest.RepeatingTimerDoesNotDrift which was relying on
strange behavior of cc::OrderedSimpleTaskRunner when
setAutoAdvanceNowToPendingTasks is false.

BUG=657517
Committed: https://crrev.com/98561e7b7897f88fbceed76c57cefa990c2cb90a
Cr-Commit-Position: refs/heads/master@{#426545}

[alex clarke (OOO till 29th), 2016-10-20 14:39:13]

The CQ bit was checked by alexclarke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-20 14:39:36]

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

[alex clarke (OOO till 29th), 2016-10-20 14:39:38]

alexclarke@chromium.org changed reviewers:
+ haraken@chromium.org

[alex clarke (OOO till 29th), 2016-10-20 14:39:39]

PTAL

[haraken, 2016-10-20 14:44:55]

LGTM

[commit-bot: I haz the power, 2016-10-20 14:57:44]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-20 14:57:45]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[alex clarke (OOO till 29th), 2016-10-20 15:30:17]

The CQ bit was checked by alexclarke@chromium.org

[alex clarke (OOO till 29th), 2016-10-20 15:30:17]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://chromiumcodereview.appspot.com/2433323003/#ps10006
(title: "Fix compile")

[commit-bot: I haz the power, 2016-10-20 15:30:33]

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, 2016-10-20 18:51:05]

Committed patchset #2 (id:10006)

[commit-bot: I haz the power, 2016-10-21 13:20:43]

Description was changed from

==========
Fix TestingPlatformSupportWithMockScheduler::runForPeriodSeconds

When one calls runForPeriodSeconds(x) you naturally expect the
testing clock to alwats advance by that many seconds.

Unfortunately cc::OrderedSimpleTaskRunner is a strange beast and
the actual time advances to the last delayed task before the
deadline if any.

This patch fixes that and makes the operation of timer fast
forwarding explicit.  It also fixes a bug in
TimerTest.RepeatingTimerDoesNotDrift which was relying on
strange behavior of cc::OrderedSimpleTaskRunner when
setAutoAdvanceNowToPendingTasks is false.

BUG=657517
==========

to

==========
Fix TestingPlatformSupportWithMockScheduler::runForPeriodSeconds

When one calls runForPeriodSeconds(x) you naturally expect the
testing clock to alwats advance by that many seconds.

Unfortunately cc::OrderedSimpleTaskRunner is a strange beast and
the actual time advances to the last delayed task before the
deadline if any.

This patch fixes that and makes the operation of timer fast
forwarding explicit.  It also fixes a bug in
TimerTest.RepeatingTimerDoesNotDrift which was relying on
strange behavior of cc::OrderedSimpleTaskRunner when
setAutoAdvanceNowToPendingTasks is false.

BUG=657517

Committed: https://crrev.com/98561e7b7897f88fbceed76c57cefa990c2cb90a
Cr-Commit-Position: refs/heads/master@{#426545}
==========

[commit-bot: I haz the power, 2016-10-21 13:20:44]

Patchset 2 (id:??) landed as
https://crrev.com/98561e7b7897f88fbceed76c57cefa990c2cb90a
Cr-Commit-Position: refs/heads/master@{#426545}