Add support for eventSender.mouseScrollBy in WTR

Add support for eventSender.mouseScrollBy in WTR
https://bugs.webkit.org/show_bug.cgi?id=69189

Source/WebKit2:

Reviewed by Simon Fraser.

* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::handleWheelEvent):
* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::wheelEventSyncForTesting):
* WebProcess/WebPage/WebPage.h:
* WebProcess/WebPage/WebPage.messages.in:
Add sync version of wheel event handling for use in testing.

Tools:

Add implementation of eventSender.mouseScrollBy for the mac.

Reviewed by Simon Fraser.

* WebKitTestRunner/EventSenderProxy.h:
* WebKitTestRunner/InjectedBundle/Bindings/EventSendingController.idl:
* WebKitTestRunner/InjectedBundle/EventSendingController.cpp:
(WTR::EventSendingController::keyDown):
(WTR::EventSendingController::mouseScrollBy):
* WebKitTestRunner/InjectedBundle/EventSendingController.h:
* WebKitTestRunner/TestController.cpp:
(WTR::TestController::didReceiveSynchronousMessageFromInjectedBundle):
* WebKitTestRunner/mac/EventSenderProxy.mm:
(WTR::EventSenderProxy::mouseScrollBy):

LayoutTests:

Reviewed by Simon Fraser.

* platform/mac-wk2/Skipped:
Removes tests that used eventSender.mouseScrollBy.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@96439 268f45cc-cd09-0410-ab3c-d52691b4dbfc