scheduler: Disable per-frame timer scheduling

scheduler: Disable per-frame timer scheduling

Disable per-frame timer scheduling for now since it is causing crashes
in situations where the underlying timer task runner becomes null.

BUG=536656, 510398
Committed: https://crrev.com/936d50e735f683407b3fe5cee3de43d2a0fc0045
Cr-Commit-Position: refs/heads/master@{#351096}

[Sami, 2015-09-28 16:38:46]

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

[alex clarke (OOO till 29th), 2015-09-28 16:44:32]

lgtm

[Rick Byers, 2015-09-28 16:48:46]

rbyers@chromium.org changed reviewers:
+ rbyers@chromium.org

[Rick Byers, 2015-09-28 16:48:47]

RS LGTM

[Sami, 2015-09-28 16:49:04]

The CQ bit was checked by skyostil@chromium.org

[commit-bot: I haz the power, 2015-09-28 16:50:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1370193002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1370193002/20001

[commit-bot: I haz the power, 2015-09-28 19:16:49]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-28 19:17:45]

Patchset 2 (id:??) landed as
https://crrev.com/936d50e735f683407b3fe5cee3de43d2a0fc0045
Cr-Commit-Position: refs/heads/master@{#351096}