Revert of Add DeadlineOverrun step to the RendererSchedulerIdlePeriod trace event.

Revert of Add DeadlineOverrun step to the RendererSchedulerIdlePeriod trace event. (patchset #1 id:1 of https://codereview.chromium.org/908473002/)

Reason for revert:
http://crbug.com/456940#c17

Original issue's description:
> Add DeadlineOverrun step to the RendererSchedulerIdlePeriod trace event.
>
> Adds a deadline overrun step to the RendererSchedulerIdlePeriod trace event
> to make it obvious when an idle period lasts longer than its deadline.
>
> Also adds a TRACE_EVENT_ASYNC_STEP_INTO_WITH_TIMESTAMP0 which is required
> to add the step at the appropriate time.
>
> BUG=455713
>
> Committed: https://crrev.com/a38b72b5f1ec147bb961e9045ca0c165f428d5e4
> Cr-Commit-Position: refs/heads/master@{#315042}

TBR=nduca@chromium.org,skyostil@chromium.org,dsinclair@chromium.org,rmcilroy@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=455713, 456940
Committed: https://crrev.com/58c1206d7b8cacb0e59e14fcd8b21a41a2b5945d
Cr-Commit-Position: refs/heads/master@{#315989}

[gab, 2015-02-12 16:14:04]

Created Revert of Add DeadlineOverrun step to the RendererSchedulerIdlePeriod
trace event.

[gab, 2015-02-12 16:14:21]

The CQ bit was checked by gab@chromium.org

[commit-bot: I haz the power, 2015-02-12 16:14:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/916223004/1

[commit-bot: I haz the power, 2015-02-12 16:14:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-12 16:15:38]

Patchset 1 (id:??) landed as
https://crrev.com/58c1206d7b8cacb0e59e14fcd8b21a41a2b5945d
Cr-Commit-Position: refs/heads/master@{#315989}