Remove Quirk shouldDisableContentChangeObserver() for YouTube.com

https://bugs.webkit.org/show_bug.cgi?id=264234
rdar://117975999

Reviewed by Tim Horton.

This removes the Quirk which had been set for YouTube in the context
of the iPad Pro, where people could not click on thumbnails on
search and results page.
https://bugs.webkit.org/show_bug.cgi?id=249740
it was then later extended to cover the full domain of YouTube.
https://bugs.webkit.org/show_bug.cgi?id=263789
YouTube team fixed the issue on their side. It removes the need for
this specific Quirk.

We probably want to take another look at
Quirks::shouldDisableContentChangeObserverTouchEventAdjustment()
and if it is still needed, but to minimize the effect of this fix,
it will be handled in another PR if necessary.

* Source/WebCore/page/Quirks.cpp:
(WebCore::Quirks::shouldDisableContentChangeObserver const): Deleted.
* Source/WebCore/page/Quirks.h:
* Source/WebCore/page/ios/ContentChangeObserver.cpp:
(WebCore::ContentChangeObserver::isContentChangeObserverEnabled):
* Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::handleSyntheticClick):
(WebKit::WebPage::completeSyntheticClick):

Canonical link: https://commits.webkit.org/270256@main

Source/WebCore/page/Quirks.cpp

@@ -193,16 +193,6 @@ bool Quirks::hasBrokenEncryptedMediaAPISupportQuirk() const
 #endif
 }
 
-// youtube.com https://bugs.webkit.org/show_bug.cgi?id=263789
-// and https://bugs.webkit.org/show_bug.cgi?id=249740
-bool Quirks::shouldDisableContentChangeObserver() const
-{
-    if (!needsQuirks())
-        return false;
-
-    return isDomain("youtube.com"_s);
-}
-
 // youtube.com https://bugs.webkit.org/show_bug.cgi?id=200609
 bool Quirks::shouldDisableContentChangeObserverTouchEventAdjustment() const
 {

Source/WebCore/page/Quirks.h

@@ -84,7 +84,6 @@ class Quirks {
     bool shouldExposeShowModalDialog() const;
     bool shouldNavigatorPluginsBeEmpty() const;
 
-    WEBCORE_EXPORT bool shouldDisableContentChangeObserver() const;
     WEBCORE_EXPORT bool shouldDispatchSyntheticMouseEventsWhenModifyingSelection() const;
     WEBCORE_EXPORT bool shouldSuppressAutocorrectionAndAutocapitalizationInHiddenEditableAreas() const;
     WEBCORE_EXPORT bool isTouchBarUpdateSupressedForHiddenContentEditable() const;

Source/WebCore/page/ios/ContentChangeObserver.cpp

@@ -67,7 +67,7 @@ static bool isHiddenBehindFullscreenElement(const Node& descendantCandidate)
 
 bool ContentChangeObserver::isContentChangeObserverEnabled()
 {
-    return m_document.settings().contentChangeObserverEnabled() && !m_document.quirks().shouldDisableContentChangeObserver();
+    return m_document.settings().contentChangeObserverEnabled();
 }
 
 bool ContentChangeObserver::isVisuallyHidden(const Node& node)

Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm

@@ -781,7 +781,7 @@ static void dispatchSyntheticMouseMove(LocalFrame& mainFrame, const WebCore::Flo
     auto& respondingDocument = nodeRespondingToClick.document();
     m_hasHandledSyntheticClick = true;
 
-    if (!respondingDocument.settings().contentChangeObserverEnabled() || respondingDocument.quirks().shouldDisableContentChangeObserver()) {
+    if (!respondingDocument.settings().contentChangeObserverEnabled()) {
         completeSyntheticClick(nodeRespondingToClick, location, modifiers, WebCore::SyntheticClickType::OneFingerTap, pointerId);
         return;
     }
@@ -915,7 +915,7 @@ static void dispatchSyntheticMouseMove(LocalFrame& mainFrame, const WebCore::Flo
     RefPtr newFocusedFrame = CheckedRef(m_page->focusController())->focusedLocalFrame();
     RefPtr<Element> newFocusedElement = newFocusedFrame ? newFocusedFrame->document()->focusedElement() : nullptr;
 
-    if (nodeRespondingToClick.document().settings().contentChangeObserverEnabled() && !nodeRespondingToClick.document().quirks().shouldDisableContentChangeObserver()) {
+    if (nodeRespondingToClick.document().settings().contentChangeObserverEnabled()) {
         auto& document = nodeRespondingToClick.document();
         // Dispatch mouseOut to dismiss tooltip content when tapping on the control bar buttons (cc, settings).
         if (document.quirks().needsYouTubeMouseOutQuirk()) {