Revert of WebWaitableEvent: implement new API with ResetPolicy and InitialState arguments

Revert of WebWaitableEvent: implement new API with ResetPolicy and InitialState arguments (patchset #4 id:60001 of https://codereview.chromium.org/1225243002/)

Reason for revert:
I think this patch is causing compile failures:
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_gn_rel/builds/107872/steps/compile%20%28with%20patch%29/logs/stdio

Original issue's description:
> WebWaitableEvent: implement new API with ResetPolicy and InitialState arguments
> 
> To support manual reset event in blink, implement new blink API
> to create WebWaitableEvent with two new arguments.
> 
> BUG=507224
> 
> Committed: https://crrev.com/bffe514b23e06dc98b3cba2601f69ade39bdb5fa
> Cr-Commit-Position: refs/heads/master@{#338045}

TBR=kinuko@chromium.org,tkent@chromium.org,toyoshim@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=507224

[pdr., 2015-07-09 18:45:20]

Created Revert of WebWaitableEvent: implement new API with ResetPolicy and
InitialState arguments

[commit-bot: I haz the power, 2015-07-09 18:46:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1229113002/1

[Takashi Toyoshima, 2015-07-09 18:47:55]

The CQ bit was unchecked by toyoshim@chromium.org

[Takashi Toyoshima, 2015-07-09 18:48:54]

Can I land this https://codereview.chromium.org/1228713005/ instread?
Otherwise, this API update looks hard to handle.

[commit-bot: I haz the power, 2015-07-09 18:49:27]

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

[pdr., 2015-07-09 19:05:39]

On 2015/07/09 at 18:48:54, toyoshim wrote:
> Can I land this https://codereview.chromium.org/1228713005/ instread?
> Otherwise, this API update looks hard to handle.

I've closed this CL. Can you please roll out as you see fit?