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

Source/core/css/CSSSupportsRule.cpp

 /* Copyright (C) 2012 Motorola Mobility Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above
  *    copyright notice, this list of conditions and the following disclaimer in
@@ skipping 26 matching lines @@
 
 CSSSupportsRule::CSSSupportsRule(StyleRuleSupports* supportsRule, CSSStyleSheet* parent)
     : CSSGroupingRule(supportsRule, parent)
 {
 }
 
 String CSSSupportsRule::cssText() const
 {
     StringBuilder result;
 
-    result.append("@supports ");
+    result.appendLiteral("@supports ");
     result.append(conditionText());
-    result.append(" {\n");
+    result.appendLiteral(" {\n");
     appendCSSTextForItems(result);
     result.append('}');
 
     return result.toString();
 }
 
 String CSSSupportsRule::conditionText() const
 {
     return toStyleRuleSupports(m_groupRule.get())->conditionText();
 }
 
 } // namespace blink