this refers to an app, not to an activity

Author: puf

auth/README.md

@@ -125,8 +125,8 @@ can be started as follows:
 
 ```
 startActivityForResult(
-    // Get an instance of AuthUI based on the current activity (`this` in the line below)
-    AuthUI.getInstance(this).createSignInIntentBuilder().build(),
+    // Get an instance of AuthUI based on the default app
+    AuthUI.getInstance().createSignInIntentBuilder().build(),
     RC_SIGN_IN);
 ```