Move PseudoElements storage to their own object.

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

Index: third_party/WebKit/Source/core/dom/ElementRareData.h
diff --git a/third_party/WebKit/Source/core/dom/ElementRareData.h b/third_party/WebKit/Source/core/dom/ElementRareData.h
index f5570bb1d8ff1455c4704b53a5d1adf632199c24..a9b6fd0283ee759d31cb51292e1d4b16d2e7a977 100644
--- a/third_party/WebKit/Source/core/dom/ElementRareData.h
+++ b/third_party/WebKit/Source/core/dom/ElementRareData.h
@@ -163,10 +163,7 @@ private:
     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*);
 };
@@ -187,67 +184,31 @@ inline ElementRareData::ElementRareData(LayoutObject* layoutObject)
 
 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)