[Merge-M54] Fix crash on item drag in shelf.

chrome/browser/ui/ash/chrome_launcher_prefs.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_ASH_CHROME_LAUNCHER_PREFS_H_
 #define CHROME_BROWSER_UI_ASH_CHROME_LAUNCHER_PREFS_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 61 matching lines @@
 // Get the list of pinned apps from preferences.
 std::vector<std::string> GetPinnedAppsFromPrefs(
     const PrefService* prefs,
     LauncherControllerHelper* helper);
 
 // Removes information about pin position from sync model for the app.
 void RemovePinPosition(Profile* profile, const std::string& app_id);
 
 // Updates information about pin position in sync model for the app |app_id|.
 // |app_id_before| optionally specifies an app that exists right before the
-// target app. |app_id_after| optionally specifies an app that exists right
-// after the target app.
+// target app. |app_ids_after| optionally specifies sorted by position apps that
+// exist right after the target app.
 void SetPinPosition(Profile* profile,
                     const std::string& app_id,
                     const std::string& app_id_before,
-                    const std::string& app_id_after);
+                    const std::vector<std::string>& app_ids_after);
 
 // Used to propagate remote preferences to local during the first run.
 class ChromeLauncherPrefsObserver
     : public syncable_prefs::PrefServiceSyncableObserver {
  public:
   // Creates and returns an instance of ChromeLauncherPrefsObserver if the
   // profile prefs do not contain all the necessary local settings for the
   // shelf. If the local settings are present, returns null.
   static std::unique_ptr<ChromeLauncherPrefsObserver> CreateIfNecessary(
       Profile* profile);
@@ skipping 10 matching lines @@
   // Profile prefs. Not owned.
   syncable_prefs::PrefServiceSyncable* prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeLauncherPrefsObserver);
 };
 
 }  // namespace launcher
 }  // namespace ash
 
 #endif  // CHROME_BROWSER_UI_ASH_CHROME_LAUNCHER_PREFS_H_