remove EnrollmentCertificateUploaderTest.DBusFailureRetry

This test item seems ineffective since the very beginning. Unlike
machine certificate uploader, this uploader doesn't rely on cryptohome
client to check the key status. The observasion is also validated by
flipping the bool flag inside the callback in the test item and the test
is still passed.

Thus, let's remove it.

Change-Id: Iea3d231be5c82537e542902103ee2793914dde03
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2303742
Commit-Queue: Leo Lai <cylai@google.com>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789815}

chrome/browser/chromeos/attestation/enrollment_certificate_uploader_impl_unittest.cc

@@ -128,24 +128,5 @@ TEST_F(EnrollmentCertificateUploaderTest, NewCertificate) {
   Run(true /* expected_status */);
 }
 
-TEST_F(EnrollmentCertificateUploaderTest, DBusFailureRetry) {
-  SetupMocks();
-  // Simulate a DBus failure.
-  cryptohome_client_.SetServiceIsAvailable(false);
-
-  // Emulate delayed service initialization.
-  // Run() instantiates an Observer, which synchronously calls
-  // TpmAttestationDoesKeyExist() and fails. During this call, we make the
-  // service available in the next run, so on retry, it will successfully
-  // return the result.
-  base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::BindOnce(
-                     [](FakeCryptohomeClient* cryptohome_client) {
-                       cryptohome_client->SetServiceIsAvailable(true);
-                     },
-                     base::Unretained(&cryptohome_client_)));
-  Run(true /* expected_status */);
-}
-
 }  // namespace attestation
 }  // namespace chromeos