Initial ResizeObserver implementation

third_party/WebKit/Source/core/dom/ElementRareData.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 23 matching lines @@
 #include "core/dom/CompositorProxiedPropertySet.h"
 #include "core/style/ComputedStyle.h"
 
 namespace blink {
 
 struct SameSizeAsElementRareData : NodeRareData {
     short indices[1];
     LayoutSize sizeForResizing;
     IntSize scrollOffset;
     void* pointers[10];
-    Member<void*> persistentMember[3];
+    Member<void*> persistentMember[4];
 };
 
 CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* ownerElement)
 {
     if (!m_cssomWrapper)
         m_cssomWrapper = new InlineCSSStyleDeclaration(ownerElement);
     return *m_cssomWrapper;
 }
 
 InlineStylePropertyMap& ElementRareData::ensureInlineStylePropertyMap(Element* ownerElement)
 {
     if (!m_cssomMapWrapper) {
         m_cssomMapWrapper = new InlineStylePropertyMap(ownerElement);
     }
     return *m_cssomMapWrapper;
 }
 
 AttrNodeList& ElementRareData::ensureAttrNodeList()
 {
     if (!m_attrNodeList)
         m_attrNodeList = new AttrNodeList;
     return *m_attrNodeList;
 }
 
+ResizeObservationSet& ElementRareData::ensureResizeObserverData()
+{
+    if (!m_resizeObserverData)
+        m_resizeObserverData = new ResizeObservationSet();
+    return *m_resizeObserverData;
+}
+
 DEFINE_TRACE_AFTER_DISPATCH(ElementRareData)
 {
     visitor->trace(m_dataset);
     visitor->trace(m_classList);
     visitor->trace(m_shadow);
     visitor->trace(m_attributeMap);
     visitor->trace(m_attrNodeList);
     visitor->trace(m_elementAnimations);
     visitor->trace(m_cssomWrapper);
     visitor->trace(m_cssomMapWrapper);
     visitor->trace(m_pseudoElementData);
     visitor->trace(m_customElementDefinition);
     visitor->trace(m_intersectionObserverData);
+    visitor->trace(m_resizeObserverData);
     NodeRareData::traceAfterDispatch(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS_AFTER_DISPATCH(ElementRareData)
 {
     visitor->traceWrappers(m_attributeMap);
     visitor->traceWrappers(m_dataset);
     visitor->traceWrappers(m_classList);
     NodeRareData::traceWrappersAfterDispatch(visitor);
 }
 
 static_assert(sizeof(ElementRareData) == sizeof(SameSizeAsElementRareData), "ElementRareData should stay small");
 
 } // namespace blink