Auto hide app list on Windows when it loses focus.

ash/shell/app_list.cc

Index: ash/shell/app_list.cc
diff --git a/ash/shell/app_list.cc b/ash/shell/app_list.cc
index cd3a0faceacf28c24bcd366d7011d51ab6081fee..c18d9daff60a1bbb3a5ab1d7b7bc7e6b7f67cc5c 100644
--- a/ash/shell/app_list.cc
+++ b/ash/shell/app_list.cc
@@ -279,6 +279,14 @@ class ExampleAppListViewDelegate : public app_list::AppListViewDelegate {
       Shell::GetInstance()->ToggleAppList();
   }
 
+  virtual void ViewClosing() OVERRIDE {
+    // Nothing needs to be done.
+  }
+
+  virtual void ViewActivationChanged(bool active) OVERRIDE {
+    // Nothing needs to be done.
+  }
+
   app_list::AppListModel* model_;
 
   DISALLOW_COPY_AND_ASSIGN(ExampleAppListViewDelegate);