mash: Convert shelf to wm::WmWindow types, part 1

ash/shell/window_watcher.cc

 // 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.
 
 #include "ash/shell/window_watcher.h"
 
 #include <utility>
 
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/shelf/shelf.h"
@@ skipping 27 matching lines @@
     DCHECK(window->children().empty());
     window->RemoveObserver(watcher_);
   }
 
   void RootWindowAdded(aura::Window* root) {
     aura::Window* panel_container =
         ash::Shell::GetContainer(root, kShellWindowId_PanelContainer);
     panel_container->AddObserver(watcher_);
 
     aura::Window* container =
-        Shelf::ForWindow(root)->shelf_widget()->window_container();
+        ash::Shell::GetContainer(root, kShellWindowId_ShelfContainer);
     container->AddObserver(this);
     for (size_t i = 0; i < container->children().size(); ++i)
       container->children()[i]->AddObserver(watcher_);
   }
 
   void RootWindowRemoved(aura::Window* root) {
     aura::Window* panel_container =
         ash::Shell::GetContainer(root, kShellWindowId_PanelContainer);
     panel_container->RemoveObserver(watcher_);
 
     aura::Window* container =
-        Shelf::ForWindow(root)->shelf_widget()->window_container();
+        ash::Shell::GetContainer(root, kShellWindowId_ShelfContainer);
     container->RemoveObserver(this);
     for (size_t i = 0; i < container->children().size(); ++i)
       container->children()[i]->RemoveObserver(watcher_);
   }
 
  private:
   WindowWatcher* watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceWindowWatcher);
 };
@@ skipping 77 matching lines @@
 void WindowWatcher::OnDisplayRemoved(const display::Display& old_display) {
   // All windows in the display has already been removed, so no need to
   // remove observers.
 }
 
 void WindowWatcher::OnDisplayMetricsChanged(const display::Display&, uint32_t) {
 }
 
 }  // namespace shell
 }  // namespace ash