Revert "Addressing Fred's comments"

This reverts commit bc6ec5c

Author: ankitaj224

firebase-installations/src/main/java/com/google/firebase/installations/GetIdListener.java

@@ -0,0 +1,43 @@
+// Copyright 2019 Google LLC
+//
+// 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 com.google.firebase.installations;
+
+import com.google.android.gms.tasks.TaskCompletionSource;
+import com.google.firebase.installations.local.PersistedInstallationEntry;
+
+class GetIdListener implements StateListener {
+  final TaskCompletionSource<String> taskCompletionSource;
+
+  public GetIdListener(TaskCompletionSource<String> taskCompletionSource) {
+    this.taskCompletionSource = taskCompletionSource;
+  }
+
+  @Override
+  public boolean onStateReached(PersistedInstallationEntry persistedInstallationEntry) {
+    if (persistedInstallationEntry.isUnregistered()
+        || persistedInstallationEntry.isRegistered()
+        || persistedInstallationEntry.isErrored()) {
+      taskCompletionSource.trySetResult(persistedInstallationEntry.getFirebaseInstallationId());
+      return true;
+    }
+    return false;
+  }
+
+  @Override
+  public boolean onException(
+      PersistedInstallationEntry persistedInstallationEntry, Exception exception) {
+    return false;
+  }
+}