Make calls to AtomicString(const String&) explicit in dom/

Source/core/dom/Attr.cpp

Index: Source/core/dom/Attr.cpp
diff --git a/Source/core/dom/Attr.cpp b/Source/core/dom/Attr.cpp
index b67b2818f656b511133a9961d0c73f0178ec4041..0a2cb9dccbbcf814bd4091faa1d2fb10f2a288e8 100644
--- a/Source/core/dom/Attr.cpp
+++ b/Source/core/dom/Attr.cpp
@@ -143,7 +143,9 @@ void Attr::setValue(const AtomicString& value, ExceptionState&)
 
 void Attr::setNodeValue(const String& v)
 {
-    setValue(v, IGNORE_EXCEPTION);
+    // Attr uses AtomicString type for its value to save memory as there
+    // is duplication among Elements' attributes values.
+    setValue(AtomicString(v), IGNORE_EXCEPTION);
 }
 
 PassRefPtr<Node> Attr::cloneNode(bool /*deep*/)