Move shelf item tooltip flag from delegate to item.

ash/common/test/test_shelf_item_delegate.cc

Index: ash/common/test/test_shelf_item_delegate.cc
diff --git a/ash/common/test/test_shelf_item_delegate.cc b/ash/common/test/test_shelf_item_delegate.cc
index 6983a1edf91e1fa92041498d1ca2f63817fe9b7f..985a705f63e9b84af11f76fda662b9aa0282f8e2 100644
--- a/ash/common/test/test_shelf_item_delegate.cc
+++ b/ash/common/test/test_shelf_item_delegate.cc
@@ -42,10 +42,6 @@ bool TestShelfItemDelegate::CanPin() const {
   return true;
 }
 
-bool TestShelfItemDelegate::ShouldShowTooltip() {
-  return true;
-}
-
 void TestShelfItemDelegate::Close() {}
 
 }  // namespace test