https://bugs.webkit.org/show_bug.cgi?id=69381

Reviewed by Sam Weinig.

Add a m_snapRubberbandTimerIsActive member variable to ScrollElasticityController
and use it instead of checking whether the m_snapRubberbandTimer is active.

Eventually, ScrollElasticityControllerClient will have two member functions for starting
and stopping the timer, and the ScrollElasticityController will call them at the appropriate times.

* platform/mac/ScrollAnimatorMac.mm:
(WebCore::ScrollAnimatorMac::handleWheelEvent):
(WebCore::ScrollAnimatorMac::beginScrollGesture):
It's OK to stop the timer unconditionally.

(WebCore::ScrollAnimatorMac::snapRubberBand):
(WebCore::ScrollAnimatorMac::snapRubberBandTimerFired):
* platform/mac/ScrollElasticityController.h:
* platform/mac/ScrollElasticityController.mm:
(WebCore::ScrollElasticityController::ScrollElasticityController):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@96652 268f45cc-cd09-0410-ab3c-d52691b4dbfc