Add AbstractThreadedSyncAdapter#onUnsyncableAccount API

This allows for an SyncAdapter to defer all onPerformSync calls (and the
admission check for those) until the adapter is ready to accept those
calls.

Test: atest android.content.cts.AccountAccessSameCertTest
      atest android.content.cts.ContentResolverSyncTestCase
      atest android.content.cts.DeferSyncTest
      atest com.android.cts.content.CtsSyncAccountAccessOtherCertTestCases
      Set up a user and work account and waited until their gmail
      synced.

Bug: 72459220
Change-Id: I8f9ab735d64189578ccdd1c3e1d7b7c5383b8ee9
diff --git a/core/java/android/content/ISyncAdapterUnsyncableAccountCallback.aidl b/core/java/android/content/ISyncAdapterUnsyncableAccountCallback.aidl
new file mode 100644
index 0000000..a738ac2
--- /dev/null
+++ b/core/java/android/content/ISyncAdapterUnsyncableAccountCallback.aidl
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.content;
+
+/**
+ * Callback for {@link ISyncAdapter#onUnsyncableAccount}
+ * @hide
+ */
+oneway interface ISyncAdapterUnsyncableAccountCallback {
+    /**
+     * Deliver the result for {@link ISyncAdapter#onUnsyncableAccount}
+     *
+     * @param isReady Iff {@code false} account is not synced.
+     */
+    void onUnsyncableAccountDone(boolean isReady);
+}