Remove some unused linked_ptr.h includes in c/b/extensions/api

chrome/browser/extensions/api/language_settings_private/language_settings_private_api.cc

 // Copyright 2015 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.
 
 #include "chrome/browser/extensions/api/language_settings_private/language_settings_private_api.h"
 
 #include <algorithm>
 #include <map>
 #include <memory>
 #include <string>
 #include <unordered_set>
 #include <utility>
 #include <vector>
 
 #include "base/i18n/rtl.h"
-#include "base/memory/linked_ptr.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/language_settings_private/language_settings_private_delegate.h"
 #include "chrome/browser/extensions/api/language_settings_private/language_settings_private_delegate_factory.h"
@@ skipping 582 matching lines @@
                               input_method_list.end(), input_method_id);
   if (pos != input_method_list.end()) {
     input_method_list.erase(pos);
     prefs->SetString(pref_name, base::JoinString(input_method_list, ","));
   }
 #endif
   return RespondNow(NoArguments());
 }
 
 }  // namespace extensions