Move PseudoElements storage to their own object.

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

 /*
  * Copyright (C) 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 145 matching lines @@
     Member<InlineCSSStyleDeclaration> m_cssomWrapper;
     Member<InlineStylePropertyMap> m_cssomMapWrapper;
     OwnPtr<CompositorProxiedPropertySet> m_proxiedProperties;
 
     Member<ElementAnimations> m_elementAnimations;
     Member<NodeIntersectionObserverData> m_intersectionObserverData;
 
     RefPtr<ComputedStyle> m_computedStyle;
     Member<V0CustomElementDefinition> m_customElementDefinition;
 
-    Member<PseudoElement> m_generatedBefore;
-    Member<PseudoElement> m_generatedAfter;
-    Member<PseudoElement> m_generatedFirstLetter;
-    Member<PseudoElement> m_backdrop;
+    Member<PseudoElementData> m_pseudoElementData;
 
     explicit ElementRareData(LayoutObject*);
 };
 
 inline LayoutSize defaultMinimumSizeForResizing()
 {
     return LayoutSize(LayoutUnit::max(), LayoutUnit::max());
 }
 
 inline ElementRareData::ElementRareData(LayoutObject* layoutObject)
     : NodeRareData(layoutObject)
     , m_tabindex(0)
     , m_minimumSizeForResizing(defaultMinimumSizeForResizing())
     , m_classList(nullptr)
 {
     m_isElementRareData = true;
 }
 
 inline ElementRareData::~ElementRareData()
 {
-    DCHECK(!m_generatedBefore);
-    DCHECK(!m_generatedAfter);
-    DCHECK(!m_generatedFirstLetter);
-    DCHECK(!m_backdrop);
 }
 
 inline bool ElementRareData::hasPseudoElements() const
 {
-    return m_generatedBefore || m_generatedAfter || m_backdrop || m_generatedFirstLetter;
+    return (m_pseudoElementData && m_pseudoElementData->hasPseudoElements());
 }
 
 inline void ElementRareData::clearPseudoElements()
 {
-    setPseudoElement(PseudoIdBefore, nullptr);
-    setPseudoElement(PseudoIdAfter, nullptr);
-    setPseudoElement(PseudoIdBackdrop, nullptr);
-    setPseudoElement(PseudoIdFirstLetter, nullptr);
+    if (m_pseudoElementData)

[sof, 2016/05/05 06:54:41]

How about (unconditionally) doing m_pseudoElementData.clear() ? i.e., the
purpose of this clearing operation is to detach the ElementRareData from its
pseudo elements.

[ramya.v, 2016/05/05 08:57:09]

If we do unconditionally, if clearPseudoElements is called before calling
setPseudoElement, it would result in a crash because m_pseudoElementData won't
be initialized by then. 

[sof, 2016/05/05 13:21:25]

m_pseudoElementClearData.clear() would work just fine and is sufficient.

[ramya.v, 2016/05/06 04:07:13]

Hi added suggested changes. Few tests are failing with this. Could you please
take a look? Thanks
https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/...

+        m_pseudoElementData->clearPseudoElements();
 }
 
 inline void ElementRareData::setPseudoElement(PseudoId pseudoId, PseudoElement* element)
 {
-    switch (pseudoId) {
-    case PseudoIdBefore:
-        if (m_generatedBefore)
-            m_generatedBefore->dispose();
-        m_generatedBefore = element;
-        break;
-    case PseudoIdAfter:
-        if (m_generatedAfter)
-            m_generatedAfter->dispose();
-        m_generatedAfter = element;
-        break;
-    case PseudoIdBackdrop:
-        if (m_backdrop)
-            m_backdrop->dispose();
-        m_backdrop = element;
-        break;
-    case PseudoIdFirstLetter:
-        if (m_generatedFirstLetter)
-            m_generatedFirstLetter->dispose();
-        m_generatedFirstLetter = element;
-        break;
-    default:
-        ASSERT_NOT_REACHED();
-    }
+    if (!m_pseudoElementData)
+        m_pseudoElementData = PseudoElementData::create();
+    m_pseudoElementData->setPseudoElement(pseudoId, element);
 }
 
 inline PseudoElement* ElementRareData::pseudoElement(PseudoId pseudoId) const
 {
-    switch (pseudoId) {
-    case PseudoIdBefore:
-        return m_generatedBefore.get();
-    case PseudoIdAfter:
-        return m_generatedAfter.get();
-    case PseudoIdBackdrop:
-        return m_backdrop.get();
-    case PseudoIdFirstLetter:
-        return m_generatedFirstLetter.get();
-    default:
-        return 0;
-    }
+    if (!m_pseudoElementData)
+        return nullptr;
+    return m_pseudoElementData->pseudoElement(pseudoId);
 }
 
 inline void ElementRareData::incrementCompositorProxiedProperties(uint32_t properties)
 {
     ensureCompositorProxiedPropertySet().increment(properties);
 }
 
 inline void ElementRareData::decrementCompositorProxiedProperties(uint32_t properties)
 {
     m_proxiedProperties->decrement(properties);
     if (m_proxiedProperties->isEmpty())
         clearCompositorProxiedPropertySet();
 }
 
 inline CompositorProxiedPropertySet& ElementRareData::ensureCompositorProxiedPropertySet()
 {
     if (!m_proxiedProperties)
         m_proxiedProperties = CompositorProxiedPropertySet::create();
     return *m_proxiedProperties;
 }
 
 } // namespace blink
 
 #endif // ElementRareData_h