Use a direct include of strings headers in content/p*/.

content/public/common/file_chooser_params.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 CONTENT_PUBLIC_COMMON_FILE_CHOOSER_PARAMS_H_
 #define CONTENT_PUBLIC_COMMON_FILE_CHOOSER_PARAMS_H_
 
 #include <vector>
 
 #include "base/files/file_path.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // Struct used by WebContentsDelegate.
 struct CONTENT_EXPORT FileChooserParams {
   FileChooserParams();
   ~FileChooserParams();
 
   enum Mode {
@@ skipping 27 matching lines @@
 #if defined(OS_ANDROID)
   // Used to select items other than files, i.e. camera/mic. See
   // SelectFileDialog.java for more details.
   string16 capture;
 #endif
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_FILE_CHOOSER_PARAMS_H_