Add LoadState reporting to the mojo proxy resolver.

net/base/load_states.h

 // 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.
 
 #ifndef NET_BASE_LOAD_STATES_H__
 #define NET_BASE_LOAD_STATES_H__
 
+#include "base/callback_forward.h"
 #include "base/strings/string16.h"
 
 namespace net {
 
 // These states correspond to the lengthy periods of time that a resource load
 // may be blocked and unable to make progress.
 enum LoadState {
 
 #define LOAD_STATE(label) LOAD_STATE_ ## label,
 #include "net/base/load_states_list.h"
 #undef LOAD_STATE
 
 };
 
 // Some states, like LOAD_STATE_WAITING_FOR_DELEGATE, are associated with extra
 // data that describes more precisely what the delegate (for example) is doing.
 // This class provides an easy way to hold a load state with an extra parameter.
 struct LoadStateWithParam {
   LoadState state;
   base::string16 param;
   LoadStateWithParam() : state(LOAD_STATE_IDLE) {}
   LoadStateWithParam(LoadState state, const base::string16& param)
       : state(state), param(param) {}
 };
 
+template <typename RequestHandle>

[eroman, 2015/03/06 05:13:01]

I don't feel this belongs in the generic load_states.h file since it is only
used by the proxy code.

[Sam McNally, 2015/03/06 09:33:02]

Done.

+using LoadStateChangedCallback =
+    const base::Callback<void(RequestHandle, LoadState)>;
+
 }  // namespace net
 
 #endif  // NET_BASE_LOAD_STATES_H__