Use invalidation sets for :lang changes.

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

Index: third_party/WebKit/Source/core/html/HTMLElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLElement.cpp b/third_party/WebKit/Source/core/html/HTMLElement.cpp
index c6a1ece4f304306bf68d423f96d7f7043a2f0c60..42a3af0e8427bc5ecb101fd51fb4e5f3ecce4145 100644
--- a/third_party/WebKit/Source/core/html/HTMLElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLElement.cpp
@@ -359,11 +359,13 @@ const AtomicString& HTMLElement::eventNameForAttributeName(const QualifiedName&
 
 void HTMLElement::parseAttribute(const QualifiedName& name, const AtomicString& oldValue, const AtomicString& value)
 {
-    if (name == tabindexAttr)
+    if (name == tabindexAttr || name == XMLNames::langAttr)
         return Element::parseAttribute(name, oldValue, value);
 
     if (name == dirAttr) {
         dirAttributeChanged(value);
+    } else if (name == langAttr) {
+        pseudoStateChanged(CSSSelector::PseudoLang);
     } else {
         const AtomicString& eventName = eventNameForAttributeName(name);
         if (!eventName.isNull())