[WebSocket] Merge duplicated HTTP headers for devtools

Source/platform/network/WebSocketHandshakeRequest.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 29 matching lines @@
 
 WebSocketHandshakeRequest::WebSocketHandshakeRequest()
     : HTTPRequest()
 {
 }
 
 WebSocketHandshakeRequest::~WebSocketHandshakeRequest()
 {
 }
 
+void WebSocketHandshakeRequest::addAndMergeHeader(HTTPHeaderMap* map, const AtomicString& name, const AtomicString& value)
+{
+    HTTPHeaderMap::AddResult result = map->add(name, value);
+    if (!result.isNewEntry) {
+        // Inspector expects the "\n" separated format.
+        result.iterator->value = result.iterator->value + "\n" + String(value);
+    }
+}
+
 } // namespace WebCore