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

Source/core/css/MediaQueryExp.cpp

 /*
  * CSS Media Query
  *
  * Copyright (C) 2006 Kimmo Kinnunen <kimmo.t.kinnunen@nokia.com>.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2013 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:
@@ skipping 290 matching lines @@
 bool MediaQueryExp::operator==(const MediaQueryExp& other) const
 {
     return (other.m_mediaFeature == m_mediaFeature)
         && ((!other.m_expValue.isValid() && !m_expValue.isValid())
             || (other.m_expValue.isValid() && m_expValue.isValid() && other.m_expValue.equals(m_expValue)));
 }
 
 String MediaQueryExp::serialize() const
 {
     StringBuilder result;
-    result.append("(");
+    result.append('(');
     result.append(m_mediaFeature.lower());
     if (m_expValue.isValid()) {
-        result.append(": ");
+        result.appendLiteral(": ");
         result.append(m_expValue.cssText());
     }
-    result.append(")");
+    result.append(')');
 
     return result.toString();
 }
 
 static inline String printNumber(double number)
 {
     return Decimal::fromDouble(number).toString();
 }
 
 String MediaQueryExpValue::cssText() const
 {
     StringBuilder output;
     if (isValue) {
         output.append(printNumber(value));
         output.append(CSSPrimitiveValue::unitTypeToString(unit));
     } else if (isRatio) {
         output.append(printNumber(numerator));
-        output.append("/");
+        output.append('/');
         output.append(printNumber(denominator));
     } else if (isID) {
         output.append(getValueName(id));
     }
 
     return output.toString();
 }
 
 } // namespace