[Telemetry] Fix image_decoding_measurement timeout.

[Telemetry] Fix image_decoding_measurement timeout.

util.WaitFor polls which is not appropriate for PerformActionAndWaitForNavigate.

Since DispatchNotifications blocks in recv until it gets some data, there is no
need to poll at an interval. Instead, we should call recv again as soon as
possible after dispatching a notification.

In the case of the image decoding measurement, it runs timeline recording. There
were so many timeline messages to receive that we were not always getting to the
important Page.navigate message before timing out.

Example:
http://build.chromium.org/p/chromium.perf/builders/Linux%20Perf%20%281%29/builds/27098

BUG=314375
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=232959

[dtu, 2013-11-05 00:13:51]

lgtdoge


THIS IS THE BEST PASS_TIME_LEFT_TO_FUNC WAS THE BANE OF MY EXISLGTMENCE

[tonyg, 2013-11-05 00:14:49]

On 2013/11/05 00:13:51, dtu wrote:
> lgtdoge
> 
> 
> THIS IS THE BEST PASS_TIME_LEFT_TO_FUNC WAS THE BANE OF MY EXISLGTMENCE

Thanks... Moar lolz

[commit-bot: I haz the power, 2013-11-05 00:44:09]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tonyg@chromium.org/47013004/1

[commit-bot: I haz the power, 2013-11-05 01:22:57]

Retried try job too often on chromium_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=chromium_p...

[commit-bot: I haz the power, 2013-11-05 04:02:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tonyg@chromium.org/47013004/100001

[commit-bot: I haz the power, 2013-11-05 13:43:56]

Change committed as 232959