Move attributes-related methods from ElementData to AttributeCollection

Source/core/dom/ElementDataCache.cpp

Index: Source/core/dom/ElementDataCache.cpp
diff --git a/Source/core/dom/ElementDataCache.cpp b/Source/core/dom/ElementDataCache.cpp
index 7e21c15b4a1adb54d51f5f3e18324a8ca87fde39..23ddd2f86cf719f7f14cbf7f015f3aaae57a3df4 100644
--- a/Source/core/dom/ElementDataCache.cpp
+++ b/Source/core/dom/ElementDataCache.cpp
@@ -38,7 +38,7 @@ inline unsigned attributeHash(const Vector<Attribute>& attributes)
 
 inline bool hasSameAttributes(const Vector<Attribute>& attributes, ShareableElementData& elementData)
 {
-    if (attributes.size() != elementData.attributeCount())
+    if (attributes.size() != elementData.attributes().size())
         return false;
     return !memcmp(attributes.data(), elementData.m_attributeArray, attributes.size() * sizeof(Attribute));
 }