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

chrome/browser/ui/app_list/search/search_provider.h

 // Copyright 2013 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_APP_LIST_SEARCH_SEARCH_PROVIDER_H_
 #define CHROME_BROWSER_UI_APP_LIST_SEARCH_SEARCH_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 
 namespace app_list {
 
 class ChromeSearchResult;
 
 class SearchProvider {
  public:
   typedef ScopedVector<ChromeSearchResult> Results;
   typedef base::Closure ResultChangedCallback;
 
@@ skipping 22 matching lines @@
 
   ResultChangedCallback result_changed_callback_;
   Results results_;
 
   DISALLOW_COPY_AND_ASSIGN(SearchProvider);
 };
 
 }  // namespace app_list
 
 #endif  // CHROME_BROWSER_UI_APP_LIST_SEARCH_SEARCH_PROVIDER_H_