Use mojo Shelf interfaces for both mash and classic ash.

chrome/browser/ui/ash/chrome_shell_delegate.cc

Index: chrome/browser/ui/ash/chrome_shell_delegate.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.cc b/chrome/browser/ui/ash/chrome_shell_delegate.cc
index dd16a4bceca2ff9dc54dcd0165f5b93507bde7f2..8f4e9b703bab95c0f6f4d2ee64b4eb444a7a9239 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.cc
@@ -434,8 +434,7 @@ app_list::AppListPresenter* ChromeShellDelegate::GetAppListPresenter() {
 ash::ShelfDelegate* ChromeShellDelegate::CreateShelfDelegate(
     ash::ShelfModel* model) {
   if (!shelf_delegate_) {
-    shelf_delegate_ =
-        ChromeLauncherControllerImpl::CreateInstance(nullptr, model);
+    shelf_delegate_ = new ChromeLauncherControllerImpl(nullptr, model);
     shelf_delegate_->Init();
   }
   return shelf_delegate_;