Make sure advancing non-zero time delta for mock timer in testScrollLatencyFromTimeline

Make sure advancing non-zero time delta for mock timer in testScrollLatencyFromTimeline

This is a speculative fix for the flaky test
RenderingStatsUnitTest.testScrollLatencyFromTimeline  (crbug.com/358673)

I am not sure about the root cause and can't repro this locally.
Buy inspecting the code I feel there could be problems if the
default timer.Advance() advances 0ms. So lets always pass in explicit
low & high parameters into timer.Advance(low, high) and see if this fix
the flaky test.

Note: the root cause could have been fixed by 
https://src.chromium.org/viewvc/chrome?revision=261034&view=revision

This is CL could be just a nice add-on.
BUG=358673
TEST=unittests RenderingStatsUnitTest.* pass.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=261464

[ernstm, 2014-04-01 23:10:11]

On 2014/04/01 22:05:19, Yufeng Shen wrote:

Please wait until https://codereview.chromium.org/221353002/ has landed and make
your changes on top of it. 221353002 adds a few more Advance() calls that should
get explicit low and high values passed in.

[Yufeng Shen (Slow to review), 2014-04-02 18:00:11]

On 2014/04/01 23:10:11, ernstm wrote:
> On 2014/04/01 22:05:19, Yufeng Shen wrote:
> 
> Please wait until https://codereview.chromium.org/221353002/ has landed and
make
> your changes on top of it. 221353002 adds a few more Advance() calls that
should
> get explicit low and high values passed in.

rebased on top of 221353002.

[ernstm, 2014-04-02 23:12:08]

On 2014/04/02 18:00:11, Yufeng Shen wrote:
> On 2014/04/01 23:10:11, ernstm wrote:
> > On 2014/04/01 22:05:19, Yufeng Shen wrote:
> > 
> > Please wait until https://codereview.chromium.org/221353002/ has landed and
> make
> > your changes on top of it. 221353002 adds a few more Advance() calls that
> should
> > get explicit low and high values passed in.
> 
> rebased on top of 221353002.

LGTM

[Yufeng Shen (Slow to review), 2014-04-03 00:43:24]

The CQ bit was checked by miletus@chromium.org

[commit-bot: I haz the power, 2014-04-03 00:45:54]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/miletus@chromium.org/220113008/20001

[commit-bot: I haz the power, 2014-04-03 01:00:23]

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

[commit-bot: I haz the power, 2014-04-03 01:00:24]

Try jobs failed on following builders:
  tryserver.chromium on win_chromium_compile_dbg

[Yufeng Shen (Slow to review), 2014-04-03 03:02:06]

The CQ bit was checked by miletus@chromium.org

[commit-bot: I haz the power, 2014-04-03 03:06:29]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/miletus@chromium.org/220113008/20001

[commit-bot: I haz the power, 2014-04-03 08:32:59]

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

[commit-bot: I haz the power, 2014-04-03 08:32:59]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[Yufeng Shen (Slow to review), 2014-04-03 17:25:47]

The CQ bit was checked by miletus@chromium.org

[commit-bot: I haz the power, 2014-04-03 17:26:52]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/miletus@chromium.org/220113008/20001

[commit-bot: I haz the power, 2014-04-03 17:28:14]

Change committed as 261464