Make WebSocket available again in service workers

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

 /*
  * Copyright (C) 2013 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 156 matching lines @@
   m_url = url;
   Vector<String> protocols;
   // Avoid placing an empty token in the Vector when the protocol string is
   // empty.
   if (!protocol.isEmpty()) {
     // Since protocol is already verified and escaped, we can simply split
     // it.
     protocol.split(", ", true, protocols);
   }
 
-  if (document()->frame()) {
+  if (document()->frame() && document()->frame()->interfaceProvider()) {
     // Initialize the WebSocketHandle with the frame's InterfaceProvider to
     // provide the WebSocket implementation with context about this frame.
     // This is important so that the browser can show UI associated with
     // the WebSocket (e.g., for certificate errors).
     m_handle->initialize(document()->frame()->interfaceProvider());
   } else {
     m_handle->initialize(Platform::current()->interfaceProvider());
   }
   m_handle->connect(url, protocols, document()->getSecurityOrigin(),
                     document()->firstPartyForCookies(), document()->userAgent(),
@@ skipping 465 matching lines @@
   WebSocketChannel::trace(visitor);
 }
 
 std::ostream& operator<<(std::ostream& ostream,
                          const DocumentWebSocketChannel* channel) {
   return ostream << "DocumentWebSocketChannel "
                  << static_cast<const void*>(channel);
 }
 
 }  // namespace blink