Update from https://crrev.com/311076

net/dns/mdns_client_impl.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_DNS_MDNS_CLIENT_IMPL_H_
 #define NET_DNS_MDNS_CLIENT_IMPL_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 91 matching lines @@
 class MDnsListenerImpl;
 
 class NET_EXPORT_PRIVATE MDnsClientImpl : public MDnsClient {
  public:
   // The core object exists while the MDnsClient is listening, and is deleted
   // whenever the number of listeners reaches zero. The deletion happens
   // asychronously, so destroying the last listener does not immediately
   // invalidate the core.
   class Core : public base::SupportsWeakPtr<Core>, MDnsConnection::Delegate {
    public:
-    explicit Core(MDnsClientImpl* client);
+    Core();
     ~Core() override;
 
     // Initialize the core. Returns true on success.
     bool Init(MDnsSocketFactory* socket_factory);
 
     // Send a query with a specific rrtype and name. Returns true on success.
     bool SendQuery(uint16 rrtype, std::string name);
 
     // Add/remove a listener to the list of listeners.
     void AddListener(MDnsListenerImpl* listener);
@@ skipping 27 matching lines @@
     void OnRecordRemoved(const RecordParsed* record);
 
     void NotifyNsecRecord(const RecordParsed* record);
 
     // Delete and erase the observer list for |key|. Only deletes the observer
     // list if is empty.
     void CleanupObserverList(const ListenerKey& key);
 
     ListenerMap listeners_;
 
-    MDnsClientImpl* client_;
     MDnsCache cache_;
 
     base::CancelableClosure cleanup_callback_;
     base::Time scheduled_cleanup_;
 
     scoped_ptr<MDnsConnection> connection_;
 
     DISALLOW_COPY_AND_ASSIGN(Core);
   };
 
@@ skipping 129 matching lines @@
   MDnsClientImpl* client_;
 
   bool started_;
   int flags_;
 
   DISALLOW_COPY_AND_ASSIGN(MDnsTransactionImpl);
 };
 
 }  // namespace net
 #endif  // NET_DNS_MDNS_CLIENT_IMPL_H_