Revert 252943@main for causing constant flickering on aa.com

https://bugs.webkit.org/show_bug.cgi?id=244879

Unreviewed. Reverts 252943@main.

* LayoutTests/TestExpectations:
* LayoutTests/fast/dom/HTMLLinkElement/link-preload-load-once-expected.txt: Removed.
* LayoutTests/fast/dom/HTMLLinkElement/link-preload-load-once.html: Removed.
* LayoutTests/fast/dom/HTMLLinkElement/link-stylesheet-load-once-expected.txt: Removed.
* LayoutTests/fast/dom/HTMLLinkElement/link-stylesheet-load-once.html: Removed.
* LayoutTests/imported/w3c/web-platform-tests/html/semantics/document-metadata/the-link-element/link-multiple-error-events-expected.txt:
* LayoutTests/imported/w3c/web-platform-tests/html/semantics/document-metadata/the-link-element/link-multiple-load-events-expected.txt:
* LayoutTests/platform/mac-wk1/fast/dom/HTMLLinkElement/link-preload-load-once-expected.txt: Removed.
* LayoutTests/platform/win/fast/dom/HTMLLinkElement/link-preload-load-once-expected.txt: Removed.
* Source/WebCore/html/HTMLLinkElement.cpp:
(WebCore::HTMLLinkElement::HTMLLinkElement):
(WebCore::HTMLLinkElement::parseAttribute):
(WebCore::HTMLLinkElement::notifyLoadedSheetAndAllCriticalSubresources):
* Source/WebCore/html/HTMLLinkElement.h:
* Source/WebCore/html/LinkRelAttribute.h:
(WebCore::operator==): Deleted.
(WebCore::operator!=): Deleted.

Canonical link: https://commits.webkit.org/254213@main

LayoutTests/TestExpectations

@@ -672,6 +672,8 @@ imported/w3c/web-platform-tests/html/browsers/sandboxing/sandbox-disallow-script
 imported/w3c/web-platform-tests/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.infinity.html [ Skip ]
 imported/w3c/web-platform-tests/html/rendering/replaced-elements/embedded-content-rendering-rules/audio-controls-002.html [ Skip ]
 imported/w3c/web-platform-tests/html/rendering/replaced-elements/svg-inline-sizing/svg-inline.html [ Skip ]
+imported/w3c/web-platform-tests/html/semantics/document-metadata/the-link-element/link-multiple-error-events.html [ Skip ]
+imported/w3c/web-platform-tests/html/semantics/document-metadata/the-link-element/link-multiple-load-events.html [ Skip ]
 imported/w3c/web-platform-tests/html/semantics/embedded-content/the-iframe-element/iframe_navigate_ancestor-1.sub.html [ Skip ]
 imported/w3c/web-platform-tests/html/semantics/forms/historical-search-event.html [ Skip ]
 imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-summary-element/anchor-with-inline-element.html [ Skip ]

LayoutTests/imported/w3c/web-platform-tests/html/semantics/document-metadata/the-link-element/link-multiple-error-events-expected.txt

@@ -1,3 +1,5 @@
 
-PASS Check if the <link>'s error event fires for each stylesheet it fails to load
+Harness Error (TIMEOUT), message = null
+
+TIMEOUT Check if the <link>'s error event fires for each stylesheet it fails to load Test timed out
 

LayoutTests/imported/w3c/web-platform-tests/html/semantics/document-metadata/the-link-element/link-multiple-load-events-expected.txt

@@ -1,3 +1,5 @@
 
-PASS Check if the <link>'s load event fires for each stylesheet it loads
+Harness Error (TIMEOUT), message = null
+
+TIMEOUT Check if the <link>'s load event fires for each stylesheet it loads Test timed out
 

Source/WebCore/html/HTMLLinkElement.cpp

@@ -92,6 +92,7 @@ inline HTMLLinkElement::HTMLLinkElement(const QualifiedName& tagName, Document&
     , m_disabledState(Unset)
     , m_loading(false)
     , m_createdByParser(createdByParser)
+    , m_firedLoad(false)
     , m_loadedResource(false)
     , m_isHandlingBeforeLoad(false)
     , m_allowPrefetchLoadAndErrorForTesting(false)
@@ -166,13 +167,10 @@ void HTMLLinkElement::setDisabledState(bool disabled)
 void HTMLLinkElement::parseAttribute(const QualifiedName& name, const AtomString& value)
 {
     if (name == relAttr) {
-        auto parsedRel = LinkRelAttribute(document(), value);
-        auto didMutateRel = parsedRel != m_relAttribute;
-        m_relAttribute = parsedRel;
+        m_relAttribute = LinkRelAttribute(document(), value);
         if (m_relList)
             m_relList->associatedAttributeValueChanged(value);
-        if (didMutateRel)
-            process();
+        process();
         return;
     }
     if (name == hrefAttr) {
@@ -561,8 +559,11 @@ DOMTokenList& HTMLLinkElement::relList()
 
 void HTMLLinkElement::notifyLoadedSheetAndAllCriticalSubresources(bool errorOccurred)
 {
+    if (m_firedLoad)
+        return;
     m_loadedResource = !errorOccurred;
     linkLoadEventSender().dispatchEventSoon(*this);
+    m_firedLoad = true;
 }
 
 void HTMLLinkElement::startLoadingDynamicSheet()

Source/WebCore/html/HTMLLinkElement.h

@@ -152,6 +152,7 @@ class HTMLLinkElement final : public HTMLElement, public CachedStyleSheetClient,
     LinkRelAttribute m_relAttribute;
     bool m_loading : 1;
     bool m_createdByParser : 1;
+    bool m_firedLoad : 1;
     bool m_loadedResource : 1;
     bool m_isHandlingBeforeLoad : 1;
     bool m_allowPrefetchLoadAndErrorForTesting : 1;

Source/WebCore/html/LinkRelAttribute.h

@@ -58,24 +58,4 @@ struct LinkRelAttribute {
     static bool isSupported(Document&, StringView);
 };
 
-inline bool operator==(const LinkRelAttribute& left, const LinkRelAttribute& right)
-{
-    return left.iconType == right.iconType
-        && left.isStyleSheet == right.isStyleSheet
-        && left.isAlternate == right.isAlternate
-        && left.isDNSPrefetch == right.isDNSPrefetch
-        && left.isLinkPreload == right.isLinkPreload
-        && left.isLinkPreconnect == right.isLinkPreconnect
-        && left.isLinkPrefetch == right.isLinkPrefetch
-#if ENABLE(APPLICATION_MANIFEST)
-        && left.isApplicationManifest == right.isApplicationManifest
-#endif
-        ;
-}
-
-inline bool operator!=(const LinkRelAttribute& left, const LinkRelAttribute& right)
-{
-    return !(left == right);
-}
-
 }