Auto hide app list on Windows when it loses focus.

ui/app_list/app_list_view.h

Index: ui/app_list/app_list_view.h
diff --git a/ui/app_list/app_list_view.h b/ui/app_list/app_list_view.h
index 89fb1f7cfe90c1083894c2fe6996206e7163d205..d5864804daeaf9465b4dc72969b315a7cc33393a 100644
--- a/ui/app_list/app_list_view.h
+++ b/ui/app_list/app_list_view.h
@@ -12,6 +12,10 @@
 #include "ui/views/bubble/bubble_delegate.h"
 #include "ui/views/controls/button/button.h"
 
+namespace views {
+class Widget;
+}
+
 namespace app_list {
 
 class AppListModel;
@@ -73,6 +77,11 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDelegateView,
                                   int action_index,
                                   int event_flags) OVERRIDE;
 
+  // Overridden from views::WidgetObserver:
+  virtual void OnWidgetClosing(views::Widget* widget) OVERRIDE;
+  virtual void OnWidgetActivationChanged(views::Widget* widget, bool active)
+      OVERRIDE;
+
   scoped_ptr<AppListModel> model_;
   scoped_ptr<AppListViewDelegate> delegate_;