Use a direct include of strings headers in chrome_frame/.

chrome_frame/find_dialog.h

 // 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.
 
 #ifndef CHROME_FRAME_FIND_DIALOG_H_
 #define CHROME_FRAME_FIND_DIALOG_H_
 
 #include <atlbase.h>
 #include <atlwin.h>
 
 #include "base/memory/ref_counted.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "resource.h"
 #include "grit/chrome_frame_dialogs.h"
 
 class ChromeFrameAutomationClient;
 
 class CFFindDialog : public CDialogImpl<CFFindDialog> {
  public:
   enum { IDD = IDD_CHROME_FRAME_FIND_DIALOG };
 
   BEGIN_MSG_MAP(CFFindDialog)
@@ skipping 27 matching lines @@
 
   // Store the text we searched for last to determine whether we are doing a
   // "Find" or a "Find Next".
   string16 last_find_text_;
 
   // We don't own these, and they must exist at least as long as we do.
   scoped_refptr<ChromeFrameAutomationClient> automation_client_;
 };
 
 #endif  // CHROME_FRAME_FIND_DIALOG_H_