Optimize Element::attributeChanged()

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 0c0bac11e5865c4574f89b638f7c5c9570ba7629..f49b9a9a740cf7f9dbe53045b689878019c961a3 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -1109,22 +1109,13 @@ void Element::attributeChanged(const QualifiedName& name, const AtomicString& ne
     document().incDOMTreeVersion();
 
     StyleResolver* styleResolver = document().styleResolver();
-    bool testShouldInvalidateStyle = inActiveDocument() && styleResolver && styleChangeType() < SubtreeStyleChange;
-
-    if (isStyledElement()) {
-        if (name == styleAttr) {
-            styleAttributeChanged(newValue, reason);
-        } else if (isPresentationAttribute(name)) {
-            elementData()->m_presentationAttributeStyleIsDirty = true;
-            setNeedsStyleRecalc(LocalStyleChange, StyleChangeReasonForTracing::fromAttribute(name));
-        }
-    }
 
     if (name == HTMLNames::idAttr) {
         AtomicString oldId = elementData()->idForStyleResolution();
         AtomicString newId = makeIdForStyleResolution(newValue, document().inQuirksMode());
         if (newId != oldId) {
             elementData()->setIdForStyleResolution(newId);
+            bool testShouldInvalidateStyle = inActiveDocument() && styleResolver && styleChangeType() < SubtreeStyleChange;

[Mike West, 2015/06/07 13:59:43]

Nit: You can fold this into the `if` on the next line.

[sof, 2015/06/07 19:01:15]

Or give it a better name :)

             if (testShouldInvalidateStyle)
                 document().styleEngine().idChangedForElement(oldId, newId, *this);
         }
@@ -1132,6 +1123,13 @@ void Element::attributeChanged(const QualifiedName& name, const AtomicString& ne
         classAttributeChanged(newValue);
     } else if (name == HTMLNames::nameAttr) {
         setHasName(!newValue.isNull());
+    } else if (isStyledElement()) {
+        if (name == styleAttr) {
+            styleAttributeChanged(newValue, reason);
+        } else if (isPresentationAttribute(name)) {
+            elementData()->m_presentationAttributeStyleIsDirty = true;
+            setNeedsStyleRecalc(LocalStyleChange, StyleChangeReasonForTracing::fromAttribute(name));
+        }
     }
 
     invalidateNodeListCachesInAncestors(&name, this);