Add action for each button on opt-in IME menu.

ash/app_list/app_list_presenter_delegate.cc

Index: ash/app_list/app_list_presenter_delegate.cc
diff --git a/ash/app_list/app_list_presenter_delegate.cc b/ash/app_list/app_list_presenter_delegate.cc
index bb485517dcbf8c393397938c01ffda45c8cd93cb..cf976e6a92f8ebde29f2b821057f1e18d69da649 100644
--- a/ash/app_list/app_list_presenter_delegate.cc
+++ b/ash/app_list/app_list_presenter_delegate.cc
@@ -329,6 +329,8 @@ void AppListPresenterDelegate::OnKeyboardBoundsChanging(
   UpdateBounds();
 }
 
+void AppListPresenterDelegate::OnKeyboardHidden() {}
+
 ////////////////////////////////////////////////////////////////////////////////
 // AppListPresenterDelegate, ShellObserver implementation:
 void AppListPresenterDelegate::OnShelfAlignmentChanged(WmWindow* root_window) {