Remove unused HostResolver::Observer.

net/proxy/sync_host_resolver_bridge_unittest.cc

 // Copyright (c) 2011 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.
 
 #include "net/proxy/sync_host_resolver_bridge.h"
 
 #include "base/threading/thread.h"
 #include "base/synchronization/waitable_event.h"
 #include "net/base/address_list.h"
 #include "net/base/net_errors.h"
@@ skipping 41 matching lines @@
                                const BoundNetLog& net_log) OVERRIDE {
     NOTIMPLEMENTED();
     return ERR_UNEXPECTED;
   }
 
   virtual void CancelRequest(RequestHandle req) OVERRIDE {
     EXPECT_EQ(reinterpret_cast<RequestHandle*>(1), req);
     was_request_cancelled_ = true;
   }
 
-  virtual void AddObserver(Observer* observer) OVERRIDE {
-    NOTREACHED();
-  }
-
-  virtual void RemoveObserver(Observer* observer) OVERRIDE {
-    NOTREACHED();
-  }
-
   // Waits until Resolve() has been called.
   void WaitUntilRequestIsReceived() {
     event_.Wait();
   }
 
   bool was_request_cancelled() const {
     return was_request_cancelled_;
   }
 
  private:
@@ skipping 162 matching lines @@
   // stop the IOThread, which will in turn delete the
   // SingleThreadedProxyResolver, which in turn will stop its internal
   // PAC thread (which is currently blocked waiting on the host resolve which
   // is running on IOThread).  The IOThread::Cleanup() will verify that after
   // the PAC thread is stopped, it cancels the request on the HostResolver.
 }
 
 }  // namespace
 
 }  // namespace net