Draggable peeking/fullscreen launcher with transparent background.

ui/app_list/views/contents_view.h

Index: ui/app_list/views/contents_view.h
diff --git a/ui/app_list/views/contents_view.h b/ui/app_list/views/contents_view.h
index 62a52cd291e99b3f672c9a64bdda4dc0c155021d..a27300fe26be18311ed68ef5ff5d99c992357409 100644
--- a/ui/app_list/views/contents_view.h
+++ b/ui/app_list/views/contents_view.h
@@ -26,6 +26,7 @@ namespace app_list {
 
 class AppsGridView;
 class AppListPage;
+class AppListView;
 class ApplicationDragAndDropHost;
 class AppListFolderItem;
 class AppListMainView;
@@ -44,7 +45,7 @@ class StartPageView;
 class APP_LIST_EXPORT ContentsView : public views::View,
                                      public PaginationModelObserver {
  public:
-  explicit ContentsView(AppListMainView* app_list_main_view);
+  ContentsView(AppListMainView* app_list_main_view, AppListView* app_list_view);
   ~ContentsView() override;
 
   // Initialize the pages of the launcher. Should be called after
@@ -191,6 +192,9 @@ class APP_LIST_EXPORT ContentsView : public views::View,
   // Parent view. Owned by the views hierarchy.
   AppListMainView* app_list_main_view_;
 
+  // Owned by the views hierarchy.
+  AppListView* const app_list_view_;
+
   // Maps State onto |view_model_| indices.
   std::map<AppListModel::State, int> state_to_view_;