Use a direct include of strings headers in ipc/, jingle/, media/.

jingle/notifier/listener/push_notifications_subscribe_task_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 "jingle/notifier/listener/push_notifications_subscribe_task.h"
 
 #include "base/memory/scoped_ptr.h"
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "jingle/notifier/listener/xml_element_util.h"
 #include "talk/xmpp/jid.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace buzz {
 class XmlElement;
 }
 
 namespace notifier {
 
@@ skipping 34 matching lines @@
               "<item channel=\"test_channel2\" from=\"from.test2.com\"/>"
             "</subscribe>"
           "</cli:iq>",
           jid_.BareJid().Str().c_str(), task_id_.c_str());
 
   EXPECT_EQ(expected_xml_string, XmlElementToString(*message));
 }
 
 }  // namespace notifier