Draggable peeking/fullscreen launcher with transparent background.

ui/app_list/views/start_page_view.h

Index: ui/app_list/views/start_page_view.h
diff --git a/ui/app_list/views/start_page_view.h b/ui/app_list/views/start_page_view.h
index 28f9c2e1771a0fee6ab114d19344fcb1441205b3..a810663e750f710619f5582ca90688112fe7557d 100644
--- a/ui/app_list/views/start_page_view.h
+++ b/ui/app_list/views/start_page_view.h
@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/app_list/views/app_list_page.h"
+#include "ui/app_list/views/app_list_view.h"
 
 namespace app_list {
 
@@ -25,7 +26,8 @@ class TileItemView;
 class APP_LIST_EXPORT StartPageView : public AppListPage {
  public:
   StartPageView(AppListMainView* app_list_main_view,
-                AppListViewDelegate* view_delegate);
+                AppListViewDelegate* view_delegate,
+                AppListView* app_list_view);
   ~StartPageView() override;
 
   void Reset();
@@ -50,11 +52,11 @@ class APP_LIST_EXPORT StartPageView : public AppListPage {
   void OnGestureEvent(ui::GestureEvent* event) override;
   void OnScrollEvent(ui::ScrollEvent* event) override;
 
-
  private:
   class StartPageTilesContainer;
 
   void InitInstantContainer();
+
   void MaybeOpenCustomLauncherPage();
 
   void SetCustomLauncherPageSelected(bool selected);