Remove AttributeCollection's findIndex(Attr*) by using QualifiedName

The internal Attribute and AttributeCollection need not know anything
about the web-exposed Attr.

Since Attr::qualifiedName() is not just a trivial getter, calling that
outside of the loop is probably a good idea anyway.

Review URL: https://codereview.chromium.org/1467143004

Cr-Commit-Position: refs/heads/master@{#361221}

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

@@ -33,7 +33,6 @@
 #ifndef AttributeCollection_h
 #define AttributeCollection_h
 
-#include "core/dom/Attr.h"
 #include "core/dom/Attribute.h"
 #include "wtf/Allocator.h"
 #include "wtf/Vector.h"
@@ -68,7 +67,6 @@ public:
     iterator find(const AtomicString& name, bool shouldIgnoreCase) const;
     size_t findIndex(const QualifiedName&, bool shouldIgnoreCase = false) const;
     size_t findIndex(const AtomicString& name, bool shouldIgnoreCase) const;
-    size_t findIndex(Attr*) const;
 
 protected:
     size_t findSlowCase(const AtomicString& name, bool shouldIgnoreAttributeCase) const;
@@ -183,19 +181,6 @@ inline typename AttributeCollectionGeneric<Container, ContainerMemberType>::iter
     return nullptr;
 }
 
-template <typename Container, typename ContainerMemberType>
-size_t AttributeCollectionGeneric<Container, ContainerMemberType>::findIndex(Attr* attr) const
-{
-    // This relies on the fact that Attr's QualifiedName == the Attribute's name.
-    iterator end = this->end();
-    unsigned index = 0;
-    for (iterator it = begin(); it != end; ++it, ++index) {
-        if (it->name() == attr->qualifiedName())
-            return index;
-    }
-    return kNotFound;
-}
-
 template <typename Container, typename ContainerMemberType>
 size_t AttributeCollectionGeneric<Container, ContainerMemberType>::findSlowCase(const AtomicString& name, bool shouldIgnoreAttributeCase) const
 {

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

@@ -2201,7 +2201,7 @@ PassRefPtrWillBeRawPtr<Attr> Element::removeAttributeNode(Attr* attr, ExceptionS
 
     synchronizeAttribute(attr->qualifiedName());
 
-    size_t index = elementData()->attributes().findIndex(attr);
+    size_t index = elementData()->attributes().findIndex(attr->qualifiedName());
     if (index == kNotFound) {
         exceptionState.throwDOMException(NotFoundError, "The attribute was not found on this element.");
         return nullptr;