Migrate websockets from url+lineNumber to SourceLocation.

third_party/WebKit/Source/modules/websockets/DOMWebSocket.cpp

 /*
  * Copyright (C) 2011 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 492 matching lines @@
             // reason might contain unpaired surrogates. Reconstruct it from
             // utf8.
             cleansedReason = String::fromUTF8(utf8.data(), utf8.length());
         }
     }
 
     if (m_state == CLOSING || m_state == CLOSED)
         return;
     if (m_state == CONNECTING) {
         m_state = CLOSING;
-        m_channel->fail("WebSocket is closed before the connection is established.", WarningMessageLevel, String(), 0);
+        m_channel->fail("WebSocket is closed before the connection is established.", WarningMessageLevel, nullptr);
         return;
     }
     m_state = CLOSING;
     if (m_channel)
         m_channel->close(code, cleansedReason);
 }
 
 const KURL& DOMWebSocket::url() const
 {
     return m_url;
@@ skipping 190 matching lines @@
 DEFINE_TRACE(DOMWebSocket)
 {
     visitor->trace(m_channel);
     visitor->trace(m_eventQueue);
     WebSocketChannelClient::trace(visitor);
     EventTargetWithInlineData::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink