Remove 'String::append' from some of the blink source.

Source/modules/websockets/WebSocketHandshake.cpp

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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.
@@ skipping 88 matching lines @@
         builder.appendNumber(url.port());
     }
     return builder.toString();
 }
 
 static const size_t maxInputSampleSize = 128;
 static String trimInputSample(const char* p, size_t len)
 {
     String s = String(p, std::min<size_t>(len, maxInputSampleSize));
     if (len > maxInputSampleSize)
-        s.append(horizontalEllipsis);
+        s = String(p, std::min<size_t>(len, maxInputSampleSize)) + horizontalEllipsis;
     return s;
 }
 
 static String generateSecWebSocketKey()
 {
     static const size_t nonceSize = 16;
     unsigned char key[nonceSize];
     cryptographicallyRandomValues(key, nonceSize);
     return base64Encode(reinterpret_cast<char*>(key), nonceSize);
 }
@@ skipping 461 matching lines @@
         }
         if (!match) {
             m_failureReason = formatHandshakeFailureReason("Sent non-empty 'Sec-WebSocket-Protocol' header but no response was received");
             return false;
         }
     }
     return true;
 }
 
 } // namespace WebCore