Extend the hang monitor timeout when an event ack is received.

Extend the hang monitor timeout when an event ack is received.

The hang monitor is supposed to wait for 30 seconds of inactivity before
deciding that a renderer is not responsive. This CL makes sure that when
waiting for multiple input events, receiving an ack is correctly interpreted
as a responsive renderer (for that moment)

BUG=336198
Committed: https://crrev.com/5919f157a98dcdd6473aeeb1ca76a2afb8c04279
Cr-Commit-Position: refs/heads/master@{#293060}

[rvargas (doing something else), 2014-09-02 22:51:22]

rvargas@chromium.org changed reviewers:
+ sky@chromium.org

[rvargas (doing something else), 2014-09-02 22:51:23]

PTAL

[sky, 2014-09-02 23:58:07]

LGTM

[rvargas (doing something else), 2014-09-03 00:06:02]

The CQ bit was checked by rvargas@chromium.org

[commit-bot: I haz the power, 2014-09-03 00:07:23]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rvargas@chromium.org/535653002/1

[commit-bot: I haz the power, 2014-09-03 02:53:22]

Committed patchset #1 (id:1) as deadfb708ff3faafdd1ea8e44433af0aa6da7e67

[commit-bot: I haz the power, 2014-09-10 03:23:12]

Patchset 1 (id:??) landed as
https://crrev.com/5919f157a98dcdd6473aeeb1ca76a2afb8c04279
Cr-Commit-Position: refs/heads/master@{#293060}