Fix face unlock for multiple users

Bug: 7152537

Not all instances of LockPatternUtils are getting updated with the current user, so
query it directly from the Activity Manager.

Change-Id: I46395c3e00feecd0edfe4228f8d7966f425519f2

core/java/com/android/internal/widget/LockPatternUtils.java

@@ -20,6 +20,7 @@ import com.android.internal.R;
 import com.android.internal.telephony.ITelephony;
 import com.google.android.collect.Lists;
 
+import android.app.ActivityManagerNative;
 import android.app.admin.DevicePolicyManager;
 import android.content.BroadcastReceiver;
 import android.content.ContentResolver;
@@ -225,7 +226,11 @@ public class LockPatternUtils {
 
     public int getCurrentUser() {
         if (Process.myUid() == Process.SYSTEM_UID) {
-            return mCurrentUserId;
+            try {
+                return ActivityManagerNative.getDefault().getCurrentUser().id;
+            } catch (RemoteException re) {
+                return mCurrentUserId;
+            }
         } else {
             throw new SecurityException("Only the system process can get the current user");
         }

policy/src/com/android/internal/policy/impl/keyguard/FaceUnlock.java

@@ -153,7 +153,8 @@ public class FaceUnlock implements BiometricSensorUnlock, Handler.Callback {
         // This must show before bind to guarantee that Face Unlock has a place to display
         show(SERVICE_STARTUP_VIEW_TIMEOUT);
         if (!mBoundToService) {
-            Log.d(TAG, "Binding to Face Unlock service");
+            Log.d(TAG, "Binding to Face Unlock service for user="
+                    + mLockPatternUtils.getCurrentUser());
             mContext.bindService(new Intent(IFaceLockInterface.class.getName()),
                     mConnection,
                     Context.BIND_AUTO_CREATE,