[iOS] Remove User-Agent quirk for facebook.com

https://bugs.webkit.org/show_bug.cgi?id=268841
rdar://121813084

Reviewed by Tim Horton.

The User-Agent quirk for facebook.com is no longer necessary and can be removed.

* Source/WebCore/page/Quirks.cpp:
(WebCore::Quirks::shouldAvoidUsingIOS17UserAgentForFacebook const): Deleted.
* Source/WebCore/page/Quirks.h:
* Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::platformUserAgent const):

Canonical link: https://commits.webkit.org/274245@main

Source/WebCore/page/Quirks.cpp

@@ -378,20 +378,6 @@ bool Quirks::shouldAvoidUsingIOS13ForGmail() const
 #endif
 }
 
-bool Quirks::shouldAvoidUsingIOS17UserAgentForFacebook() const
-{
-#if PLATFORM(IOS_FAMILY)
-    if (!needsQuirks())
-        return false;
-
-    if (!m_shouldAvoidUsingIOS17UserAgentForFacebook)
-        m_shouldAvoidUsingIOS17UserAgentForFacebook = isDomain("facebook.com"_s);
-    return m_shouldAvoidUsingIOS17UserAgentForFacebook.value();
-#else
-    return false;
-#endif
-}
-
 void Quirks::updateStorageAccessUserAgentStringQuirks(HashMap<RegistrableDomain, String>&& userAgentStringQuirks)
 {
     auto& quirks = updatableStorageAccessUserAgentStringQuirks();

Source/WebCore/page/Quirks.h

@@ -99,7 +99,6 @@ class Quirks {
     WEBCORE_EXPORT bool needsYouTubeMouseOutQuirk() const;
 
     WEBCORE_EXPORT bool shouldAvoidUsingIOS13ForGmail() const;
-    WEBCORE_EXPORT bool shouldAvoidUsingIOS17UserAgentForFacebook() const;
 
     WEBCORE_EXPORT static void updateStorageAccessUserAgentStringQuirks(HashMap<RegistrableDomain, String>&&);
     WEBCORE_EXPORT String storageAccessUserAgentStringQuirkForDomain(const URL&);
@@ -251,7 +250,6 @@ class Quirks {
     mutable std::optional<bool> m_shouldStarBeFeaturePolicyDefaultValueQuirk;
     mutable std::optional<bool> m_shouldDisableDataURLPaddingValidation;
     mutable std::optional<bool> m_needsDisableDOMPasteAccessQuirk;
-    mutable std::optional<bool> m_shouldAvoidUsingIOS17UserAgentForFacebook;
     mutable std::optional<bool> m_shouldDisableElementFullscreen;
 
     Vector<RegistrableDomain> m_subFrameDomainsForStorageAccessQuirk;

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

@@ -4638,9 +4638,6 @@ static bool selectionIsInsideFixedPositionContainer(LocalFrame& frame)
     if (osNameForUserAgent() == "iPhone OS"_s) {
         if (document->quirks().shouldAvoidUsingIOS13ForGmail())
             return standardUserAgentWithApplicationName({ }, "12_1_3"_s);
-
-        if (document->quirks().shouldAvoidUsingIOS17UserAgentForFacebook())
-            return standardUserAgentWithApplicationName({ }, "16_6_1"_s);
     }
     return String();
 }