Revert of EventSender: Added checks for missing arguments

Revert of EventSender: Added checks for missing arguments (patchset #4 id:60001 of https://codereview.chromium.org/584203003/)

Reason for revert:
This makes the fast/events/hit-test-counts.html layout test fail. Reverting for now.

http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fast%2Fevents%2Fhit-test-counts.html&testType=layout-tests

Original issue's description:
> Added checks for missing arguments in event_sender.cc. Also simplified the uses of x & y in EventSender::GestureEvent.
>
> BUG=415970
>
> Committed: https://crrev.com/302907463636d2ddfe25c5381bd1f2b64016d1c6
> Cr-Commit-Position: refs/heads/master@{#296256}

TBR=dpranke@chromium.org,rbyers@chromium.org,earthdok@chromium.org,mustaq@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=415970
Committed: https://crrev.com/f70f5fb877a526a7df23caf02831c1e9635b0fb3
Cr-Commit-Position: refs/heads/master@{#296357}

[Mads Ager (chromium), 2014-09-24 07:02:32]

Created Revert of EventSender: Added checks for missing arguments

[commit-bot: I haz the power, 2014-09-24 07:03:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/600733002/1

[commit-bot: I haz the power, 2014-09-24 07:03:35]

Committed patchset #1 (id:1) as d6e3d513e4faef3439483473cbf0f465b0d15b9d

[commit-bot: I haz the power, 2014-09-24 07:04:06]

Patchset 1 (id:??) landed as
https://crrev.com/f70f5fb877a526a7df23caf02831c1e9635b0fb3
Cr-Commit-Position: refs/heads/master@{#296357}