ash: Move AppList support to ShelfWidget, expose ShelfWidget in WmShelf

ash/common/shelf/shelf_widget.cc

Index: ash/common/shelf/shelf_widget.cc
diff --git a/ash/common/shelf/shelf_widget.cc b/ash/common/shelf/shelf_widget.cc
index d1f5c72aef3c44b605630a40901fe66578a96455..1cbbeafcbf69a6af823eefe33c4d2e537e8eda27 100644
--- a/ash/common/shelf/shelf_widget.cc
+++ b/ash/common/shelf/shelf_widget.cc
@@ -521,6 +521,15 @@ gfx::Rect ShelfWidget::GetScreenBoundsOfItemIconForWindow(WmWindow* window) {
                    bounds.height());
 }
 
+AppListButton* ShelfWidget::GetAppListButton() const {
+  return shelf_view_->GetAppListButton();
+}
+
+app_list::ApplicationDragAndDropHost*
+ShelfWidget::GetDragAndDropHostForAppList() {
+  return shelf_view_;
+}
+
 void ShelfWidget::OnWidgetActivationChanged(views::Widget* widget,
                                             bool active) {
   activating_as_fallback_ = false;