Draggable peeking/fullscreen launcher with transparent background.

ash/app_list/app_list_delegate_impl.cc

Index: ash/app_list/app_list_delegate_impl.cc
diff --git a/ash/app_list/app_list_delegate_impl.cc b/ash/app_list/app_list_delegate_impl.cc
index ef2f8c9b579a4da651b5222e1ce36f44e52c55d6..6df6dd849722dabb57d1dc6939cdb0a2aaf2af26 100644
--- a/ash/app_list/app_list_delegate_impl.cc
+++ b/ash/app_list/app_list_delegate_impl.cc
@@ -10,6 +10,7 @@
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
+#include "ui/app_list/app_list_features.h"
 #include "ui/app_list/presenter/app_list.h"
 
 namespace ash {
@@ -35,6 +36,9 @@ void AppListDelegateImpl::OnAppListVisibilityChanged(bool visible,
     app_list_button->OnAppListShown();
   else
     app_list_button->OnAppListDismissed();
+
+  if (app_list::features::IsFullscreenAppListEnabled())
+    Shelf::ForWindow(root_window)->OnAppListIsActive();
 }
 
 }  // namespace ash