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

jingle/notifier/listener/notification_defines_unittest.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 <string>
 
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "jingle/notifier/listener/notification_defines.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace notifier {
 namespace {
 
 class NotificationTest : public testing::Test {};
 
 // Create a notification with binary data in the data field.
 // Converting it to string shouldn't cause a crash.
 TEST_F(NotificationTest, BinaryData) {
   const char kNonUtf8Data[] = { '\xff', '\0' };
   EXPECT_FALSE(IsStringUTF8(kNonUtf8Data));
   Notification notification;
   notification.data = kNonUtf8Data;
   EXPECT_EQ("{ channel: \"\", data: \"\\u00FF\" }", notification.ToString());
 }
 
 }  // namespace
 }  // namespace notifier