mash: Replace int ShelfIDs with AppLaunchID strings.

ash/shell/window_watcher.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_WINDOW_WATCHER_H_
 #define ASH_SHELL_WINDOW_WATCHER_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 16 matching lines @@
 // TODO(sky): fix this class, its a bit broke with workspace2.
 
 // WindowWatcher is responsible for listening for newly created windows and
 // creating items on the Shelf for them.
 class WindowWatcher : public aura::WindowObserver,
                       public display::DisplayObserver {
  public:
   WindowWatcher();
   ~WindowWatcher() override;
 
-  aura::Window* GetWindowByID(ash::ShelfID id);
+  aura::Window* GetWindowByID(const ShelfID& id);
 
   // aura::WindowObserver overrides:
   void OnWindowAdded(aura::Window* new_window) override;
   void OnWillRemoveWindow(aura::Window* window) override;
 
   // display::DisplayObserver overrides:
   void OnDisplayAdded(const display::Display& new_display) override;
   void OnDisplayRemoved(const display::Display& old_display) override;
   void OnDisplayMetricsChanged(const display::Display& display,
                                uint32_t metrics) override;
 
  private:
   class WorkspaceWindowWatcher;
 
-  typedef std::map<ash::ShelfID, aura::Window*> IDToWindow;
+  typedef std::map<ShelfID, aura::Window*> IDToWindow;
 
   // Maps from window to the id we gave it.
   IDToWindow id_to_window_;
 
   std::unique_ptr<WorkspaceWindowWatcher> workspace_window_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowWatcher);
 };
 
 }  // namespace shell
 }  // namespace ash
 
 #endif  // ASH_SHELL_WINDOW_WATCHER_H_