Use StringBuilder::appendLiteral() / StringBuilder::append(char) when possible

Source/core/css/CSSImportRule.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2008, 2009, 2010, 2012 Apple 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.
  *
@@ skipping 44 matching lines @@
 MediaList* CSSImportRule::media() const
 {
     if (!m_mediaCSSOMWrapper)
         m_mediaCSSOMWrapper = MediaList::create(m_importRule->mediaQueries(), const_cast<CSSImportRule*>(this));
     return m_mediaCSSOMWrapper.get();
 }
 
 String CSSImportRule::cssText() const
 {
     StringBuilder result;
-    result.append("@import url(\"");
+    result.appendLiteral("@import url(\"");
     result.append(m_importRule->href());
-    result.append("\")");
+    result.appendLiteral("\")");
 
     if (m_importRule->mediaQueries()) {
         String mediaText = m_importRule->mediaQueries()->mediaText();
         if (!mediaText.isEmpty()) {
             result.append(' ');
             result.append(mediaText);
         }
     }
     result.append(';');
 
@@ skipping 18 matching lines @@
 
 void CSSImportRule::trace(Visitor* visitor)
 {
     visitor->trace(m_importRule);
     visitor->trace(m_mediaCSSOMWrapper);
     visitor->trace(m_styleSheetCSSOMWrapper);
     CSSRule::trace(visitor);
 }
 
 } // namespace blink