Avoid calling hasAttribute() and then getAttribute() for performance

Avoid calling hasAttribute() and then getAttribute() for performance.
This causes the attribute to be looked up (linear search) twice instead
of once if we call getAttribute() directly and then check if the returned
AtomicString is null.

R=eseidel@chromium.org, eseidel, rwlbuis

Review URL: https://codereview.chromium.org/183763033

git-svn-id: svn://svn.chromium.org/blink/trunk@168423 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/editing/EditingStyle.cpp

@@ -290,12 +290,13 @@ void HTMLAttributeEquivalent::addToStyle(Element* element, EditingStyle* style)
 PassRefPtrWillBeRawPtr<CSSValue> HTMLAttributeEquivalent::attributeValueAsCSSValue(Element* element) const
 {
     ASSERT(element);
-    if (!element->hasAttribute(m_attrName))
+    const AtomicString& value = element->getAttribute(m_attrName);
+    if (value.isNull())
         return nullptr;
 
     RefPtr<MutableStylePropertySet> dummyStyle;
     dummyStyle = MutableStylePropertySet::create();
-    dummyStyle->setProperty(m_propertyID, element->getAttribute(m_attrName));
+    dummyStyle->setProperty(m_propertyID, value);
     return dummyStyle->getPropertyCSSValue(m_propertyID);
 }
 
@@ -319,10 +320,11 @@ HTMLFontSizeEquivalent::HTMLFontSizeEquivalent()
 PassRefPtrWillBeRawPtr<CSSValue> HTMLFontSizeEquivalent::attributeValueAsCSSValue(Element* element) const
 {
     ASSERT(element);
-    if (!element->hasAttribute(m_attrName))
+    const AtomicString& value = element->getAttribute(m_attrName);
+    if (value.isNull())
         return nullptr;
     CSSValueID size;
-    if (!HTMLFontElement::cssValueFromFontSizeNumber(element->getAttribute(m_attrName), size))
+    if (!HTMLFontElement::cssValueFromFontSizeNumber(value, size))
         return nullptr;
     return CSSPrimitiveValue::createIdentifier(size);
 }

third_party/WebKit/Source/core/editing/SplitElementCommand.cpp

@@ -93,8 +93,9 @@ void SplitElementCommand::doUnapply()
         m_element2->insertBefore(children[i].get(), refChild.get(), IGNORE_EXCEPTION);
 
     // Recover the id attribute of the original element.
-    if (m_element1->hasAttribute(HTMLNames::idAttr))
-        m_element2->setAttribute(HTMLNames::idAttr, m_element1->getAttribute(HTMLNames::idAttr));
+    const AtomicString& id = m_element1->getAttribute(HTMLNames::idAttr);
+    if (!id.isNull())
+        m_element2->setAttribute(HTMLNames::idAttr, id);
 
     m_element1->remove(IGNORE_EXCEPTION);
 }

third_party/WebKit/Source/core/html/HTMLAnchorElement.cpp

@@ -393,12 +393,13 @@ bool HTMLAnchorElement::isLiveLink() const
 
 void HTMLAnchorElement::sendPings(const KURL& destinationURL)
 {
-    if (!hasAttribute(pingAttr) || !document().settings() || !document().settings()->hyperlinkAuditingEnabled())
+    const AtomicString& pingValue = getAttribute(pingAttr);
+    if (pingValue.isNull() || !document().settings() || !document().settings()->hyperlinkAuditingEnabled())
         return;
 
     UseCounter::count(document(), UseCounter::HTMLAnchorElementPingAttribute);
 
-    SpaceSplitString pingURLs(getAttribute(pingAttr), false);
+    SpaceSplitString pingURLs(pingValue, false);
     for (unsigned i = 0; i < pingURLs.size(); i++)
         PingLoader::sendPing(document().frame(), document().completeURL(pingURLs[i]), destinationURL);
 }

third_party/WebKit/Source/core/inspector/DOMEditor.cpp

@@ -175,9 +175,10 @@ public:
 
     virtual bool perform(ExceptionState& exceptionState) OVERRIDE
     {
-        m_hadAttribute = m_element->hasAttribute(m_name);
+        const AtomicString& value = m_element->getAttribute(m_name);
+        m_hadAttribute = !value.isNull();
         if (m_hadAttribute)
-            m_oldValue = m_element->getAttribute(m_name);
+            m_oldValue = value;
         return redo(exceptionState);
     }