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

Source/core/css/parser/BisonCSSParserTest.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/parser/BisonCSSParser.h"
 
 #include "core/css/CSSTimingFunctionValue.h"
 #include "core/css/MediaList.h"
 #include "core/css/StyleRule.h"
@@ skipping 61 matching lines @@
     const WillBeHeapVector<OwnPtrWillBeMember<MediaQuery> >& queryVector = querySet.queryVector();
     size_t queryVectorSize = queryVector.size();
     StringBuilder output;
 
     for (size_t i = 0; i < queryVectorSize; ) {
         String queryText = queryVector[i]->cssText();
         output.append(queryText);
         ++i;
         if (i >= queryVectorSize)
             break;
-        output.append(", ");
+        output.appendLiteral(", ");
     }
     ASSERT_STREQ(expected, output.toString().ascii().data());
 }
 
 TEST(BisonCSSParserTest, MediaQuery)
 {
     struct {
         const char* input;
         const char* output;
     } testCases[] = {
         {"@media s} {}", "not all"},
         {"@media } {}", "not all"},
         {"@media tv {}", "tv"},
         {"@media tv, screen {}", "tv, screen"},
         {"@media s}, tv {}", "not all, tv"},
         {"@media tv, screen and (}) {}", "tv, not all"},
     };
 
     BisonCSSParser parser(strictCSSParserContext());
 
     for (unsigned i = 0; i < ARRAY_SIZE(testCases); ++i) {
         RefPtrWillBeRawPtr<StyleRuleBase> rule = parser.parseRule(nullptr, String(testCases[i].input));
 
         EXPECT_TRUE(rule->isMediaRule());
         testMediaQuery(testCases[i].output, *static_cast<StyleRuleMedia*>(rule.get())->mediaQueries());
     }
 }
 
 } // namespace blink