Remove ash-disable-launcher-per-display flag

ash/shell.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 ASH_SHELL_H_
 #define ASH_SHELL_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 182 matching lines @@
   static const aura::Window* GetContainer(const aura::RootWindow* root_window,
                                           int container_id);
 
   // Returns the list of containers that match |container_id| in
   // all root windows. If |priority_root| is given, the container
   // in the |priority_root| will be inserted at the top of the list.
   static std::vector<aura::Window*> GetContainersFromAllRootWindows(
       int container_id,
       aura::RootWindow* priority_root);
 
-  // True if "launcher per display" feature  is enabled.
-  static bool IsLauncherPerDisplayEnabled();
-
   // True if an experimental maximize mode is enabled which forces browser and
   // application windows to be maximized only.
   static bool IsForcedMaximizeMode();
 
   void set_active_root_window(aura::RootWindow* active_root_window) {
     active_root_window_ = active_root_window;
   }
 
   // Shows the context menu for the background and launcher at
   // |location_in_screen| (in screen coordinates).
@@ skipping 383 matching lines @@
 
   // For testing only: simulate that a modal window is open
   bool simulate_modal_window_open_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_H_