Add feature requirement annotation

Test: N/A - annotation only

Change-Id: I7307b89ccce23a8327b175045fc927027ed9ce02
diff --git a/core/java/android/credentials/CredentialManager.java b/core/java/android/credentials/CredentialManager.java
index 2e63664..3a9a0f91 100644
--- a/core/java/android/credentials/CredentialManager.java
+++ b/core/java/android/credentials/CredentialManager.java
@@ -23,6 +23,7 @@
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.RequiresFeature;
 import android.annotation.RequiresPermission;
 import android.annotation.SystemService;
 import android.annotation.TestApi;
@@ -31,6 +32,7 @@
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.IntentSender;
+import android.content.pm.PackageManager;
 import android.os.Binder;
 import android.os.Bundle;
 import android.os.CancellationSignal;
@@ -57,6 +59,7 @@
  * to authenticate to the app.
  */
 @SystemService(Context.CREDENTIAL_SERVICE)
+@RequiresFeature(PackageManager.FEATURE_CREDENTIALS)
 public final class CredentialManager {
     private static final String TAG = "CredentialManager";
     private static final Bundle OPTIONS_SENDER_BAL_OPTIN = ActivityOptions.makeBasic()