Cherry-pick c602819. rdar://124128482

    Inline CustomElementElementQueue into CustomElementReactionStack
    https://bugs.webkit.org/show_bug.cgi?id=270551

    Reviewed by Chris Dumez.

    Inline CustomElementElementQueue into CustomElementReactionStack to avoid heap allocation.

    * Source/WebCore/dom/CustomElementReactionQueue.cpp:
    (WebCore::CustomElementQueue::processQueue):
    (WebCore::CustomElementReactionQueue::enqueueElementOnAppropriateElementQueue):
    (WebCore::CustomElementReactionStack::processQueue): Deleted.
    (WebCore::CustomElementReactionStack::takeElements): Deleted.
    * Source/WebCore/dom/CustomElementReactionQueue.h:
    (WebCore::CustomElementQueue::CustomElementQueue): Inlined.
    (WebCore::CustomElementQueue::~CustomElementQueue): Ditto.
    (WebCore::CustomElementQueue::isEmpty const): Added.
    (WebCore::CustomElementReactionStack::~CustomElementReactionStack):
    (WebCore::CustomElementReactionStack::takeElements): Inlined.
    * Source/WebCore/dom/GCReachableRef.h:

    Canonical link: https://commits.webkit.org/275734@main

Source/WebCore/dom/CustomElementReactionQueue.cpp

@@ -319,9 +319,6 @@ void CustomElementReactionQueue::invokeAll(Element& element)
     }
 }
 
-CustomElementQueue::CustomElementQueue() = default;
-CustomElementQueue::~CustomElementQueue() = default;
-
 inline void CustomElementQueue::add(Element& element)
 {
     ASSERT(!m_invoking);
@@ -346,7 +343,7 @@ inline void CustomElementQueue::invokeAll()
     m_elements.clear();
 }
 
-inline void CustomElementQueue::processQueue(JSC::JSGlobalObject* state)
+void CustomElementQueue::processQueue(JSC::JSGlobalObject* state)
 {
     if (!state) {
         invokeAll();
@@ -393,10 +390,7 @@ void CustomElementReactionQueue::enqueueElementOnAppropriateElementQueue(Element
         return;
     }
 
-    auto& queue = CustomElementReactionStack::s_currentProcessingStack->m_queue;
-    if (!queue)
-        queue = makeUnique<CustomElementQueue>();
-    queue->add(element);
+    CustomElementReactionStack::s_currentProcessingStack->m_queue.add(element);
 }
 
 #if ASSERT_ENABLED
@@ -405,22 +399,6 @@ unsigned CustomElementReactionDisallowedScope::s_customElementReactionDisallowed
 
 CustomElementReactionStack* CustomElementReactionStack::s_currentProcessingStack = nullptr;
 
-void CustomElementReactionStack::processQueue(JSC::JSGlobalObject* state)
-{
-    ASSERT(m_queue);
-    m_queue->processQueue(state);
-    m_queue = nullptr;
-}
-
-Vector<GCReachableRef<Element>, 4> CustomElementReactionStack::takeElements()
-{
-    if (!m_queue)
-        return { };
-    auto elements = m_queue->takeElements();
-    m_queue = nullptr;
-    return elements;
-}
-
 void CustomElementReactionQueue::processBackupQueue(CustomElementQueue& backupElementQueue)
 {
     backupElementQueue.processQueue(nullptr);

Source/WebCore/dom/CustomElementReactionQueue.h

@@ -26,6 +26,7 @@
 #pragma once
 
 #include "CustomElementFormValue.h"
+#include "Element.h"
 #include "GCReachableRef.h"
 #include "QualifiedName.h"
 #include <wtf/CheckedRef.h>
@@ -99,11 +100,12 @@ class CustomElementQueue {
     WTF_MAKE_FAST_ALLOCATED;
     WTF_MAKE_NONCOPYABLE(CustomElementQueue);
 public:
-    CustomElementQueue();
-    WEBCORE_EXPORT ~CustomElementQueue();
+    CustomElementQueue() = default;
+    ~CustomElementQueue() { ASSERT(isEmpty()); }
 
+    bool isEmpty() const { return m_elements.isEmpty(); }
     void add(Element&);
-    void processQueue(JSC::JSGlobalObject*);
+    WEBCORE_EXPORT void processQueue(JSC::JSGlobalObject*);
 
     Vector<GCReachableRef<Element>, 4> takeElements();
 
@@ -224,17 +226,15 @@ class CustomElementReactionStack : public CustomElementReactionDisallowedScope::
 
     ALWAYS_INLINE ~CustomElementReactionStack()
     {
-        if (UNLIKELY(m_queue))
-            processQueue(m_state);
+        if (UNLIKELY(!m_queue.isEmpty()))
+            m_queue.processQueue(m_state);
         s_currentProcessingStack = m_previousProcessingStack;
     }
 
-    Vector<GCReachableRef<Element>, 4> takeElements();
+    Vector<GCReachableRef<Element>, 4> takeElements() { return m_queue.takeElements(); }
 
 private:
-    WEBCORE_EXPORT void processQueue(JSC::JSGlobalObject*);
-
-    std::unique_ptr<CustomElementQueue> m_queue;
+    CustomElementQueue m_queue;
     CustomElementReactionStack* const m_previousProcessingStack;
     JSC::JSGlobalObject* const m_state;
 

Source/WebCore/dom/GCReachableRef.h

@@ -49,7 +49,7 @@ class GCReachableRefMap {
     }
 
 private:
-    static HashCountedSet<EventTarget*>& map();
+    WEBCORE_EXPORT static HashCountedSet<EventTarget*>& map();
 };
 
 template <typename T, typename = std::enable_if_t<std::is_same<T, typename std::remove_const<T>::type>::value>>