Ensure pending intent on beam notification is immutable

Bug: 159060474
Test: manual
Change-Id: I90b5212651eb88b06db266a4e6a23b8baefaf47e
(cherry picked from commit fc0910a24b2e724f4177008e0962b47a682263ce)
diff --git a/src/com/android/nfc/beam/BeamTransferManager.java b/src/com/android/nfc/beam/BeamTransferManager.java
index eff9d6b..c8a48a1 100644
--- a/src/com/android/nfc/beam/BeamTransferManager.java
+++ b/src/com/android/nfc/beam/BeamTransferManager.java
@@ -343,7 +343,8 @@
                 notBuilder.setContentText(mContext.getString(R.string.beam_tap_to_view));
                 Intent viewIntent = buildViewIntent();
                 PendingIntent contentIntent = PendingIntent.getActivity(
-                        mContext, mTransferId, viewIntent, 0, null);
+                        mContext, mTransferId, viewIntent,
+                        PendingIntent.FLAG_ONE_SHOT | PendingIntent.FLAG_IMMUTABLE, null);
 
                 notBuilder.setContentIntent(contentIntent);
             }