Introduce EventTrackingRegions::Event enum

[Constellation]

36ca2e4

Introduce EventTrackingRegions::Event enum
https://bugs.webkit.org/show_bug.cgi?id=240206

Reviewed by Mark Lam.

We noticed that EventNames 260~ AtomStrings are allocated in scrolling thread only because we are using
eventNames() for EventTrackingRegions. But since use of it is limited, we can just use enum instead.

    1. We can make EventTrackingRegions more efficient by using enum instead of String.
    2. We can save memory by avoiding EventNames string allocations & AtomStringTable registration.
    3. We can make this parameter more strictly typed compared to accepting any kind of Strings

* Source/WebKit/Shared/RemoteLayerTree/RemoteScrollingCoordinatorTransaction.cpp:
(WebKit::dump):
* Source/WebKit/Shared/WebCoreArgumentCoders.cpp:
(IPC::ArgumentCoder<EventTrackingRegions >::decode):
* Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp:
(WebKit::RemoteScrollingCoordinatorProxy::eventTrackingTypeForPoint const):
* Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.h:
* Source/WebKit/UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::updateTouchEventTracking):
* Source/WebCore/page/DebugPageOverlays.cpp:
(WebCore::NonFastScrollableRegionOverlay::drawRect):
* Source/WebCore/page/Page.cpp:
(WebCore::Page::touchEventRectsForEventForTesting):
* Source/WebCore/page/Page.h:
* Source/WebCore/page/scrolling/ScrollingCoordinator.cpp:
(WebCore::ScrollingCoordinator::absoluteEventTrackingRegionsForFrame const):
* Source/WebCore/page/scrolling/ScrollingStateFrameScrollingNode.cpp:
(WebCore::ScrollingStateFrameScrollingNode::dumpProperties const):
* Source/WebCore/page/scrolling/ScrollingTree.cpp:
(WebCore::ScrollingTree::computeWheelProcessingSteps):
(WebCore::ScrollingTree::eventTrackingTypeForPoint):
* Source/WebCore/page/scrolling/ScrollingTree.h:
* Source/WebCore/platform/EventTrackingRegions.cpp:
(WebCore::EventTrackingRegions::eventName):
(WebCore::EventTrackingRegions::trackingTypeForPoint):
(WebCore::EventTrackingRegions::uniteSynchronousRegion):
* Source/WebCore/platform/EventTrackingRegions.h:
* Source/WebCore/testing/Internals.cpp:
(WebCore::Internals::touchEventRectsForEvent):
* Source/WebCore/testing/Internals.h:

Canonical link: https://commits.webkit.org/250405@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@293967 268f45cc-cd09-0410-ab3c-d52691b4dbfc

[MenloDorian]

r=me with suggestions for improvement.

[Constellation]

Thanks!

[webkit-early-warning-system]

Commit message contains (OOPS!), blocking PR #558

[Constellation]

Landed https://commits.webkit.org/250405@main (36ca2e4)!