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

Source/core/css/MediaQuerySetTest.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 "config.h"
 #include "core/css/MediaQuery.h"
 
 #include "core/css/MediaList.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/text/StringBuilder.h"
@@ skipping 11 matching lines @@
 static void testMediaQuery(TestCase test, MediaQuerySet& querySet, bool oldParser)
 {
     StringBuilder output;
     size_t j = 0;
     while (j < querySet.queryVector().size()) {
         String queryText = querySet.queryVector()[j]->cssText();
         output.append(queryText);
         ++j;
         if (j >= querySet.queryVector().size())
             break;
-        output.append(", ");
+        output.appendLiteral(", ");
     }
     if (!oldParser || test.shouldWorkOnOldParser) {
         if (test.output)
             ASSERT_STREQ(test.output, output.toString().ascii().data());
         else
             ASSERT_STREQ(test.input, output.toString().ascii().data());
     }
 }
 
 TEST(MediaQuerySetTest, Basic)
@@ skipping 121 matching lines @@
 
     for (unsigned i = 0; testCases[i].input; ++i) {
         RefPtrWillBeRawPtr<MediaQuerySet> oldParserQuerySet = MediaQuerySet::create(testCases[i].input);
         RefPtrWillBeRawPtr<MediaQuerySet> threadSafeQuerySet = MediaQuerySet::createOffMainThread(testCases[i].input);
         testMediaQuery(testCases[i], *oldParserQuerySet, true);
         testMediaQuery(testCases[i], *threadSafeQuerySet, false);
     }
 }
 
 } // namespace