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

Source/core/inspector/ContentSearchUtils.cpp

 /*
  * Copyright (C) 2011 Google 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.
  *
@@ skipping 31 matching lines @@
 static const char regexSpecialCharacters[] = "[](){}+-*.,?\\^$|";
 }
 
 static String createSearchRegexSource(const String& text)
 {
     StringBuilder result;
     String specials(regexSpecialCharacters);
 
     for (unsigned i = 0; i < text.length(); i++) {
         if (specials.find(text[i]) != kNotFound)
-            result.append("\\");
+            result.append('\\');
         result.append(text[i]);
     }
 
     return result.toString();
 }
 
 static Vector<pair<int, String> > getScriptRegexpMatchesByLines(const ScriptRegexp* regex, const String& text)
 {
     Vector<pair<int, String> > result;
     if (text.isEmpty())
@@ skipping 116 matching lines @@
 }
 
 String findSourceMapURL(const String& content, MagicCommentType commentType, bool* deprecated)
 {
     return findMagicComment(content, "sourceMappingURL", commentType, deprecated);
 }
 
 } // namespace ContentSearchUtils
 } // namespace blink