Remove old (dead) app list code.

ash/app_list/app_list_presenter_delegate.h

Index: ash/app_list/app_list_presenter_delegate.h
diff --git a/ash/app_list/app_list_presenter_delegate.h b/ash/app_list/app_list_presenter_delegate.h
index 5ae603d057bb57722e34e5b9849c5e819f074c47..21775ea56f4e5051f2f24e3bd8c20c469f47e77b 100644
--- a/ash/app_list/app_list_presenter_delegate.h
+++ b/ash/app_list/app_list_presenter_delegate.h
@@ -72,7 +72,6 @@ class ASH_EXPORT AppListPresenterDelegate
   void OnKeyboardClosed() override;
 
   // ShellObserver overrides:
-  void OnShelfAlignmentChanged(WmWindow* root_window) override;
   void OnOverviewModeStarting() override;
   void OnMaximizeModeStarted() override;
   void OnMaximizeModeEnded() override;
@@ -83,9 +82,6 @@ class ASH_EXPORT AppListPresenterDelegate
   // Whether the app list is visible (or in the process of being shown).
   bool is_visible_ = false;
 
-  // Whether the app list should remain centered.
-  bool is_centered_ = false;
-
   // Not owned. Pointer is guaranteed to be valid while this object is alive.
   app_list::AppListPresenter* presenter_;