Use the single char overload of append() when possible.

third_party/WebKit/Source/core/css/parser/CSSParserToken.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/parser/CSSParserToken.h"
 
 #include "core/css/CSSMarkup.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/css/parser/CSSPropertyParser.h"
 #include "wtf/HashMap.h"
@@ skipping 201 matching lines @@
         builder.append('@');
         serializeIdentifier(value().toString(), builder);
         break;
     case HashToken:
         builder.append('#');
         serializeIdentifier(value().toString(), builder, (getHashTokenType() == HashTokenUnrestricted));
         break;
     case UrlToken:
         builder.append("url(");
         serializeIdentifier(value().toString(), builder);
-        return builder.append(")");
+        return builder.append(')');
     case DelimiterToken:
         if (delimiter() == '\\')
             return builder.append("\\\n");
         return builder.append(delimiter());
     case NumberToken:
         // These won't properly preserve the NumericValueType flag
         return builder.appendNumber(numericValue());
     case PercentageToken:
         builder.appendNumber(numericValue());
         return builder.append('%');
@@ skipping 60 matching lines @@
     return value >= -std::numeric_limits<float>::max()
         && value <= std::numeric_limits<float>::max();
 }
 
 bool CSSParserToken::isValidNumericValue() const
 {
     return isValidNumericValue(numericValue());
 }
 
 } // namespace blink