Avoid WebSocket::stop() being processed twice

Source/modules/websockets/WebSocket.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 471 matching lines @@
 }
 
 void WebSocket::resume()
 {
     if (m_channel)
         m_channel->resume();
 }
 
 void WebSocket::stop()
 {
-    bool pending = hasPendingActivity();
-    if (m_channel)
+    if (!hasPendingActivity()) {
+        ASSERT(!m_channel);
+        ASSERT(m_state == CLOSED);
+        return;
+    }
+    if (m_channel) {
         m_channel->disconnect();
-    m_channel = 0;
+        m_channel = 0;
+    }
     m_state = CLOSED;
     ActiveDOMObject::stop();
-    if (pending)
-        ActiveDOMObject::unsetPendingActivity(this);
+    ActiveDOMObject::unsetPendingActivity(this);
 }
 
 void WebSocket::didConnect()
 {
     LOG(Network, "WebSocket %p didConnect()", this);
     if (m_state != CONNECTING)
         return;
     ASSERT(scriptExecutionContext());
     m_state = OPEN;
     m_subprotocol = m_channel->subprotocol();
@@ skipping 89 matching lines @@
     static const size_t minimumPayloadSizeWithEightByteExtendedPayloadLength = 0x10000;
     size_t overhead = hybiBaseFramingOverhead + hybiMaskingKeyLength;
     if (payloadSize >= minimumPayloadSizeWithEightByteExtendedPayloadLength)
         overhead += 8;
     else if (payloadSize >= minimumPayloadSizeWithTwoByteExtendedPayloadLength)
         overhead += 2;
     return overhead;
 }
 
 } // namespace WebCore