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

Source/core/html/forms/ImageInputType.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 67 matching lines @@
 
     if (!element().value().isEmpty())
         encoding.appendData(name, element().value());
     return true;
 }
 
 String ImageInputType::resultForDialogSubmit() const
 {
     StringBuilder result;
     result.appendNumber(m_clickLocation.x());
-    result.append(",");
+    result.append(',');
     result.appendNumber(m_clickLocation.y());
     return result.toString();
 }
 
 bool ImageInputType::supportsValidation() const
 {
     return false;
 }
 
 static IntPoint extractClickLocation(Event* event)
@@ skipping 137 matching lines @@
 {
     return name == srcAttr || BaseButtonInputType::hasLegalLinkAttribute(name);
 }
 
 const QualifiedName& ImageInputType::subResourceAttributeName() const
 {
     return srcAttr;
 }
 
 } // namespace blink