Literal AtomicString construction can rely on strlen optimization.

third_party/WebKit/Source/core/html/forms/FileInputType.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 237 matching lines @@
     else
         UseCounter::count(*document, UseCounter::InputTypeFileSecureOrigin);
 }
 
 void FileInputType::createShadowSubtree()
 {
     ASSERT(element().shadow());
     RefPtrWillBeRawPtr<HTMLInputElement> button = HTMLInputElement::create(element().document(), 0, false);
     button->setType(InputTypeNames::button);
     button->setAttribute(valueAttr, AtomicString(locale().queryString(element().multiple() ? WebLocalizedString::FileButtonChooseMultipleFilesLabel : WebLocalizedString::FileButtonChooseFileLabel)));
-    button->setShadowPseudoId(AtomicString("-webkit-file-upload-button", AtomicString::ConstructFromLiteral));
+    button->setShadowPseudoId(AtomicString("-webkit-file-upload-button"));
     element().userAgentShadowRoot()->appendChild(button.release());
 }
 
 void FileInputType::disabledAttributeChanged()
 {
     ASSERT(element().shadow());
     if (Element* button = toElement(element().userAgentShadowRoot()->firstChild()))
         button->setBooleanAttribute(disabledAttr, element().isDisabledFormControl());
 }
 
@@ skipping 103 matching lines @@
     StringBuilder names;
     for (size_t i = 0; i < listSize; ++i) {
         names.append(fileList->item(i)->name());
         if (i != listSize - 1)
             names.append('\n');
     }
     return names.toString();
 }
 
 } // namespace blink