Use a direct include of strings headers in chrome/browser/ui/a*/.

chrome/browser/ui/android/chrome_http_auth_handler.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_BROWSER_UI_ANDROID_CHROME_HTTP_AUTH_HANDLER_H_
 #define CHROME_BROWSER_UI_ANDROID_CHROME_HTTP_AUTH_HANDLER_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "chrome/browser/ui/login/login_prompt.h"
 
 // This class facilitates communication between a native LoginHandler
 // and a Java land ChromeHttpAuthHandler, which is passed to a
 // ContentViewClient to allow it to respond to HTTP authentication requests
 // by, e.g., showing the user a login dialog.
 class ChromeHttpAuthHandler {
  public:
   ChromeHttpAuthHandler(const string16& explanation);
   ~ChromeHttpAuthHandler();
@@ skipping 44 matching lines @@
  private:
   LoginHandler* observer_;
   base::android::ScopedJavaGlobalRef<jobject> java_chrome_http_auth_handler_;
   // e.g. "The server example.com:80 requires a username and password."
   string16 explanation_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeHttpAuthHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_ANDROID_CHROME_HTTP_AUTH_HANDLER_H_