Fix crash on openning settings when DCHECK is on.

ash/shelf/shelf_model_unittest.cc

Index: ash/shelf/shelf_model_unittest.cc
diff --git a/ash/shelf/shelf_model_unittest.cc b/ash/shelf/shelf_model_unittest.cc
index 12177d7dd60336a9eaf00533fd1c24979229194d..efb67a18d58a339e6bf48e4bf68108855641ae72 100644
--- a/ash/shelf/shelf_model_unittest.cc
+++ b/ash/shelf/shelf_model_unittest.cc
@@ -69,7 +69,7 @@ class ShelfModelTest : public testing::Test {
 
     ShelfItem item;
     item.type = TYPE_APP_LIST;
-    item.id = ShelfID("AppListId");
+    item.id = ShelfID(AppListShelfItemDelegate::kAppListId);

[msw, 2017/05/05 21:45:04]

nit: include the header for this (or use something like kDummyAppId or define a
string copy here, and make kAppListId private to the cc file again)

[khmel, 2017/05/05 22:45:12]

Done.

     model_->Add(item);
     EXPECT_EQ(1, model_->item_count());