Don't throw "completed" exception

chrome/renderer/resources/extensions/test_custom_bindings.js

Index: chrome/renderer/resources/extensions/test_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/test_custom_bindings.js b/chrome/renderer/resources/extensions/test_custom_bindings.js
index 52db024275c7abdaff6801492a6f35c51fb2698d..3c5c89cde9829605f781b70fe165f47be0d1f2a3 100644
--- a/chrome/renderer/resources/extensions/test_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/test_custom_bindings.js
@@ -46,10 +46,6 @@ binding.registerCustomHook(function(api) {
       chromeTest.notifyFail('Failed ' + testsFailed + ' of ' +
                              testCount + ' tests');
     }
-
-    // Try to get the script to stop running immediately.
-    // This isn't an error, just an attempt at saying "done".
-    throw "completed";
   }
 
   var pendingCallbacks = 0;