test IWYU fixups for base

sync/notifier/p2p_invalidator.cc

 // Copyright (c) 2012 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 "sync/notifier/p2p_invalidator.h"
 
 #include <algorithm>
+#include <iterator>

[rlarocque, 2013/08/30 17:08:43]

I don't see why IWYU thought this was necessary.  

[Mostyn Bramley-Moore, 2013/08/30 17:14:48]

I didn't run IWYU on this file, but after making some of the suggested changes
in base/* this file failed to build with this message:

FAILED: ninja -t msvc -e environment.x86 -- E:\b\build\goma\gomacc.exe
"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\cl.exe" /nologo
/showIncludes /FC
@obj\chrome\browser\extensions\browser_extensions.blacklist.obj.rsp /c
..\..\chrome\browser\extensions\blacklist.cc
/Foobj\chrome\browser\extensions\browser_extensions.blacklist.obj
/Fdobj\chrome\browser_extensions.pdb 
e:\b\build\slave\win\build\src\base\stl_util.h(216) : error C2039: 'inserter' :
is not a member of 'std'
       
e:\b\build\slave\win\build\src\chrome\browser\extensions\blacklist.cc(223) : see
reference to function template instantiation 'ResultType
base::STLSetDifference<std::set<_Kty>,std::set<_Kty>,std::set<_Kty>>(const Arg1
&,const Arg2 &)' being compiled
        with
        [
            ResultType=std::set<std::string>,
            _Kty=std::string,
            Arg1=std::set<std::string>,
            Arg2=std::set<std::string>
        ]
e:\b\build\slave\win\build\src\base\stl_util.h(216) : error C3861: 'inserter':
identifier not found

So it's the use of std::inserter that requires <iterator>.

 
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "jingle/notifier/listener/push_client.h"
 #include "sync/notifier/invalidation_handler.h"
 #include "sync/notifier/invalidation_util.h"
 
 namespace syncer {
@@ skipping 275 matching lines @@
     return;
   }
   notifier::Notification notification;
   notification.channel = kSyncP2PNotificationChannel;
   notification.data = notification_data.ToString();
   DVLOG(1) << "Sending XMPP notification: " << notification.ToString();
   push_client_->SendNotification(notification);
 }
 
 }  // namespace syncer