Random crashes on the Web Thread due to Timers firing on the wrong thread in the...

Random crashes on the Web Thread due to Timers firing on the wrong thread in the UI process
https://bugs.webkit.org/show_bug.cgi?id=135132
<rdar://problem/17719832>

Reviewed by Simon Fraser.

* UIProcess/ProcessThrottler.cpp:
(WebKit::ProcessThrottler::ProcessThrottler):
(WebKit::ProcessThrottler::suspendTimerFired):
* UIProcess/ProcessThrottler.h:
* UIProcess/ios/ViewGestureControllerIOS.mm:
(WebKit::ViewGestureController::ViewGestureController):
(WebKit::ViewGestureController::swipeSnapshotWatchdogTimerFired):
* UIProcess/mac/ViewGestureController.h:
* UIProcess/mac/ViewGestureControllerMac.mm:
(WebKit::ViewGestureController::ViewGestureController):
(WebKit::ViewGestureController::swipeSnapshotWatchdogTimerFired):
We can't use WebCore timers in the UI process because of coexistence concerns
(they fire on the Web Thread if there is one!), so use RunLoop::Timer instead.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@171317 268f45cc-cd09-0410-ab3c-d52691b4dbfc