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

Source/core/css/CSSKeyframesRule.cpp

 /*
  * Copyright (C) 2007, 2008, 2012 Apple 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 the
@@ skipping 145 matching lines @@
 CSSKeyframeRule* CSSKeyframesRule::findRule(const String& s)
 {
     int i = m_keyframesRule->findKeyframeIndex(s);
     return (i >= 0) ? item(i) : 0;
 }
 
 String CSSKeyframesRule::cssText() const
 {
     StringBuilder result;
     if (isVendorPrefixed())
-        result.append("@-webkit-keyframes ");
+        result.appendLiteral("@-webkit-keyframes ");
     else
-        result.append("@keyframes ");
+        result.appendLiteral("@keyframes ");
     result.append(name());
-    result.append(" { \n");
+    result.appendLiteral(" { \n");
 
     unsigned size = length();
     for (unsigned i = 0; i < size; ++i) {
-        result.append("  ");
+        result.appendLiteral("  ");
         result.append(m_keyframesRule->keyframes()[i]->cssText());
-        result.append("\n");
+        result.append('\n');
     }
-    result.append("}");
+    result.append('}');
     return result.toString();
 }
 
 unsigned CSSKeyframesRule::length() const
 {
     return m_keyframesRule->keyframes().size();
 }
 
 CSSKeyframeRule* CSSKeyframesRule::item(unsigned index) const
 {
@@ skipping 25 matching lines @@
 {
     CSSRule::trace(visitor);
 #if ENABLE(OILPAN)
     visitor->trace(m_childRuleCSSOMWrappers);
 #endif
     visitor->trace(m_keyframesRule);
     visitor->trace(m_ruleListCSSOMWrapper);
 }
 
 } // namespace blink