[Fingerprint] Show skip button during SUW

Show a skip button during enrolling in case the user entered the flow
accidentally. The skip button will send the result code RESULT_SKIP,
which is equal to RESULT_FIRST_USER + 1, back to the starting
activity.

Bug: 22666389
Change-Id: I230b04e5150214c31536ac282d56b7b490c85ac1

src/com/android/settings/fingerprint/FingerprintEnrollFindSensor.java

@@ -76,6 +76,9 @@ public class FingerprintEnrollFindSensor extends FingerprintEnrollBase {
             if (resultCode == RESULT_FINISHED) {
                 setResult(RESULT_FINISHED);
                 finish();
+            } else if (resultCode == RESULT_SKIP) {
+                setResult(RESULT_SKIP);
+                finish();
             } else {
                 FingerprintManager fpm = getSystemService(FingerprintManager.class);
                 int enrolled = fpm.getEnrolledFingerprints().size();