mash: Cleanup ash shelf application menu code.

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index f9856ebe329bf0daba971b90669eb6deafb2ffd2..3fecf7ed26cdddb51602a3d6c5089560ec4ae31b 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -151,6 +151,8 @@ component("ash") {
     "common/shelf/overflow_button.h",
     "common/shelf/shelf_alignment_menu.cc",
     "common/shelf/shelf_alignment_menu.h",
+    "common/shelf/shelf_application_menu_model.cc",
+    "common/shelf/shelf_application_menu_model.h",
     "common/shelf/shelf_background_animator.cc",
     "common/shelf/shelf_background_animator.h",
     "common/shelf/shelf_background_animator_observer.h",
@@ -1186,6 +1188,7 @@ test("ash_unittests") {
     "common/popup_message_unittest.cc",
 
     # TODO: convert to use AshTest http://crbug.com/654494.
+    "common/shelf/shelf_application_menu_model_unittest.cc",
     "common/shelf/shelf_background_animator_unittest.cc",
     "common/shelf/shelf_button_pressed_metric_tracker_unittest.cc",
     "common/shelf/shelf_locking_manager_unittest.cc",