[Aura] Refactor and update app list window.

ui/aura_shell/shell.h

Index: ui/aura_shell/shell.h
diff --git a/ui/aura_shell/shell.h b/ui/aura_shell/shell.h
index fd0d59628b38c01b6983f9aa1b9fa60ee18da5bc..b9348cbdec0937d9b45d9bfc6a2ea68974096aaa 100644
--- a/ui/aura_shell/shell.h
+++ b/ui/aura_shell/shell.h
@@ -30,6 +30,7 @@ class Launcher;
 class ShellDelegate;
 
 namespace internal {
+class AppList;
 class DragDropController;
 class ShelfLayoutController;
 class WorkspaceController;
@@ -61,6 +62,9 @@ class AURA_SHELL_EXPORT Shell {
   // Toggles between overview mode and normal mode.
   void ToggleOverview();
 
+  // Toggles app list.
+  void ToggleAppList();
+
   ShellDelegate* delegate() { return delegate_.get(); }
   Launcher* launcher() { return launcher_.get(); }
 
@@ -85,6 +89,8 @@ class AURA_SHELL_EXPORT Shell {
 
   scoped_ptr<Launcher> launcher_;
 
+  scoped_ptr<internal::AppList> app_list_;
+
   scoped_ptr<internal::DragDropController> drag_drop_controller_;
   scoped_ptr<internal::WorkspaceController> workspace_controller_;
   scoped_ptr<internal::ShelfLayoutController> shelf_layout_controller_;