Enable mash shelf tooltips.

ash/test/shelf_view_test_api.h

Index: ash/test/shelf_view_test_api.h
diff --git a/ash/test/shelf_view_test_api.h b/ash/test/shelf_view_test_api.h
index 9d5f594a55f9f50ef33420b2e7369dc6fdd75543..9b035882dbe5088c0e3357ebb250b47ad8c13258 100644
--- a/ash/test/shelf_view_test_api.h
+++ b/ash/test/shelf_view_test_api.h
@@ -27,6 +27,7 @@ class OverflowBubble;
 class ShelfButton;
 class ShelfButtonPressedMetricTracker;
 class ShelfDelegate;
+class ShelfTooltipManager;
 class ShelfView;
 
 namespace test {
@@ -68,6 +69,9 @@ class ShelfViewTestAPI {
   // An accessor for |shelf_view|.
   ShelfView* shelf_view() { return shelf_view_; }
 
+  // An accessor for the shelf tooltip manager.
+  ShelfTooltipManager* tooltip_manager();
+
   // An accessor for overflow bubble.
   OverflowBubble* overflow_bubble();