[Tabs] Making delegate methods all optional. (#8)

willlarche · brianjmoore · commit 52b8d9679f6a · 2017-01-03T16:10:15.000-05:00
diff --git a/components/Tabs/src/MDCTabBar.h b/components/Tabs/src/MDCTabBar.h
@@ -137,6 +137,8 @@ IB_DESIGNABLE
  */
 @protocol MDCTabBarDelegate <NSObject>
 
+@optional
+
 /**
  Called before the selected item changes by user action. This method is not called for programmatic
  changes to the tab bar's selected item.
