ServiceWorkerRegistration::unregister returns false when the registration is...

ServiceWorkerRegistration::unregister returns false when the registration is already unregistered. (3/3)

1. [Blink] https://codereview.chromium.org/549093002/
2. [Chromium] https://codereview.chromium.org/554573002/
3. [Blink] this patch

BUG=390894
TEST=run_webkit_tests.py http/tests/serviceworker/unregister.html

Review URL: https://codereview.chromium.org/550093002

git-svn-id: svn://svn.chromium.org/blink/trunk@181783 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/http/tests/serviceworker/unregister.html

@@ -28,11 +28,8 @@ async_test(function(t) {
           return registration.unregister();
         })
       .then(function(value) {
-          // FIXME: Uncomment after applied the first patch.
-          // https://codereview.chromium.org/554573002
-          // See: https://crbug.com/390894#c16
-          // assert_equals(value, false,
-          //               'unregistering twice should resolve with false');
+          assert_equals(value, false,
+                        'unregistering twice should resolve with false');
           t.done();
         })
       .catch(unreached_rejection(t));