Fix a bug of PopupAlignmentDelegate on non-primary display

ash/system/web_notification/web_notification_tray_unittest.cc

Index: ash/system/web_notification/web_notification_tray_unittest.cc
diff --git a/ash/system/web_notification/web_notification_tray_unittest.cc b/ash/system/web_notification/web_notification_tray_unittest.cc
index c8a71e0544ff752f5f276170474080a77b2e4137..0b5820ccf2790d38db834d94284894ff891e8496 100644
--- a/ash/system/web_notification/web_notification_tray_unittest.cc
+++ b/ash/system/web_notification/web_notification_tray_unittest.cc
@@ -140,7 +140,7 @@ class WebNotificationTrayTest : public test::AshMDTestBase {
   }
 
   int GetPopupWorkAreaBottomForTray(WebNotificationTray* tray) {
-    return tray->popup_alignment_delegate_->GetWorkAreaBottom();
+    return tray->popup_alignment_delegate_->GetWorkArea().bottom();
   }
 
   bool IsPopupVisible() { return GetTray()->IsPopupVisible(); }