Fix more latched scrolling test flakiness and slowness

Fix more latched scrolling test flakiness and slowness
https://bugs.webkit.org/show_bug.cgi?id=133601

Reviewed by Brent Fulgham.

Source/WebKit2:

Latched scrolling tests were flakey for two reasons. First, the EventSender
wheel events were async from the web to the UI process, and the resulting
synthetic events also async from the UI to the web process. Make them sync
for testing.

Secondly, the timer-based scrolling tree commit could result in the scrolling
tree (specifically the frame node's notion of the scrollable area and content
size) not being updated before the scrolling thread starts getting wheel events.
Fix by having WebPage::wheelEventSyncForTesting() commit if necessary.

Finally remove all the now-unnecessary timeouts from the tests.

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::wheelEventSyncForTesting):

Tools:

Latched scrolling tests were flakey for two reasons. First, the EventSender
wheel events were async from the web to the UI process, and the resulting
synthetic events also async from the UI to the web process. Make them sync
for testing.

Secondly, the timer-based scrolling tree commit could result in the scrolling
tree (specifically the frame node's notion of the scrollable area and content
size) not being updated before the scrolling thread starts getting wheel events.
Fix by having WebPage::wheelEventSyncForTesting() commit if necessary.

Finally remove all the now-unnecessary timeouts from the tests.

* WebKitTestRunner/mac/EventSenderProxy.mm:
(WTR::EventSenderProxy::mouseMoveTo):
(WTR::EventSenderProxy::mouseScrollBy):
(WTR::EventSenderProxy::mouseScrollByWithWheelAndMomentumPhases):

LayoutTests:

Latched scrolling tests were flakey for two reasons. First, the EventSender
wheel events were async from the web to the UI process, and the resulting
synthetic events also async from the UI to the web process. Make them sync
for testing.

Secondly, the timer-based scrolling tree commit could result in the scrolling
tree (specifically the frame node's notion of the scrollable area and content
size) not being updated before the scrolling thread starts getting wheel events.
Fix by having WebPage::wheelEventSyncForTesting() commit if necessary.

Finally remove all the now-unnecessary timeouts from the tests.

* platform/mac-wk2/tiled-drawing/fast-scroll-div-latched-div-with-handler-expected.txt:
* platform/mac-wk2/tiled-drawing/fast-scroll-div-latched-div-with-handler.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-div-latched-div.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-div-latched-mainframe-with-handler-expected.txt:
* platform/mac-wk2/tiled-drawing/fast-scroll-div-latched-mainframe-with-handler.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-div-latched-mainframe.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-iframe-latched-iframe-with-handler.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-iframe-latched-iframe.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-iframe-latched-mainframe-with-handler-expected.txt:
* platform/mac-wk2/tiled-drawing/fast-scroll-iframe-latched-mainframe-with-handler.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-iframe-latched-mainframe.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-select-latched-mainframe-with-handler-expected.txt:
* platform/mac-wk2/tiled-drawing/fast-scroll-select-latched-mainframe-with-handler.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-select-latched-mainframe.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-select-latched-select-with-handler-expected.txt:
* platform/mac-wk2/tiled-drawing/fast-scroll-select-latched-select-with-handler.html:
* platform/mac-wk2/tiled-drawing/fast-scroll-select-latched-select.html:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@169692 268f45cc-cd09-0410-ab3c-d52691b4dbfc