Use a direct include of strings headers in remoting/.

remoting/host/disconnect_window_mac.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 
 #import "remoting/host/disconnect_window_mac.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "remoting/host/client_session_control.h"
 #include "remoting/host/host_window.h"
 #include "remoting/host/ui_strings.h"
 
 @interface DisconnectWindowController()
 - (BOOL)isRToL;
 - (void)Hide;
 @end
 
@@ skipping 270 matching lines @@
   path = [NSBezierPath bezierPath];
   [path moveToPoint:top];
   [path lineToPoint:bottom];
   [light setStroke];
   [path stroke];
 
   [context setShouldAntialias:alias];
 }
 
 @end