Add IMMUTABLE flag to AccountManager pending intents.

Bug: 174189215,177931355
Test: none
Change-Id: I11c81ce4cfb0f51a2fabf92a45d8425647df2121
(cherry picked from commit 7e615a523c)

services/core/java/com/android/server/accounts/AccountManagerService.java

@@ -3071,7 +3071,8 @@ public class AccountManagerService
                     .setContentTitle(title)
                     .setContentText(subtitle)
                     .setContentIntent(PendingIntent.getActivityAsUser(mContext, 0, intent,
-                            PendingIntent.FLAG_CANCEL_CURRENT, null, user))
+                            PendingIntent.FLAG_CANCEL_CURRENT | PendingIntent.FLAG_IMMUTABLE,
+                            null, user))
                     .build();
         installNotification(getCredentialPermissionNotificationId(
                 account, authTokenType, uid), n, packageName, user.getIdentifier());
@@ -5293,7 +5294,8 @@ public class AccountManagerService
                         .setContentTitle(String.format(notificationTitleFormat, account.name))
                         .setContentText(message)
                         .setContentIntent(PendingIntent.getActivityAsUser(
-                                mContext, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT,
+                                mContext, 0, intent,
+                                PendingIntent.FLAG_CANCEL_CURRENT | PendingIntent.FLAG_IMMUTABLE,
                                 null, new UserHandle(userId)))
                         .build();
                 installNotification(id, n, packageName, userId);