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 930f3de6d654a933348ddf794209d60e24628afd..528640c91f046f9b5d98e221ccaefe52388ea0b6 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);

[sky, 2016/10/07 22:59:37]

Does this leak?

[msw, 2016/10/07 23:13:01]

No, it's owned by the unique_ptr WmShell::shelf_delegate_:
  https://cs.chromium.org/chromium/src/ash/common/wm_shell.cc?l=134

     shelf_delegate_->Init();
   }
   return shelf_delegate_;