Reduce usage of WebString::data

Tools/DumpRenderTree/chromium/TestRunner/src/EventSender.cpp

 /*
  * Copyright (C) 2010 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 598 matching lines @@
             snprintf(functionChars, 10, "F%d", i);
             string functionKeyName(functionChars);
             if (functionKeyName == codeStr) {
                 code = VKEY_F1 + (i - 1);
                 break;
             }
         }
         if (!code) {
             WebString webCodeStr = WebString::fromUTF8(codeStr.data(), codeStr.size());
             WEBKIT_ASSERT(webCodeStr.length() == 1);
-            text = code = webCodeStr.data()[0];
+            text = code = webCodeStr.at(0);
             needsShiftKeyModifier = needsShiftModifier(code);
             if ((code & 0xFF) >= 'a' && (code & 0xFF) <= 'z')
                 code -= 'a' - 'A';
             generateChar = true;
         }
 
         if ("(" == codeStr) {
             code = '9';
             needsShiftKeyModifier = true;
         }
@@ skipping 745 matching lines @@
 {
     result->setNull();
 }
 
 void EventSender::clearKillRing(const CppArgumentList&, CppVariant* result)
 {
     result->setNull();
 }
 
 }