Refactor password metric computation.

This unifies previously duplicated code.

Bug: 30558331
Test: runtest -x frameworks/base/core/tests/coretests/src/android/app/admin/PasswordMetricsTest.java
Change-Id: I37678b83a03d4f05b9894d4b00e9a741d1a8df27
diff --git a/Android.mk b/Android.mk
index 4fea0d4..31b1276 100644
--- a/Android.mk
+++ b/Android.mk
@@ -574,6 +574,7 @@
 	frameworks/base/core/java/android/accounts/AuthenticatorDescription.aidl \
 	frameworks/base/core/java/android/accounts/Account.aidl \
 	frameworks/base/core/java/android/app/admin/SystemUpdatePolicy.aidl \
+	frameworks/base/core/java/android/app/admin/PasswordMetrics.aidl \
 	frameworks/base/core/java/android/print/PrintDocumentInfo.aidl \
 	frameworks/base/core/java/android/print/PageRange.aidl \
 	frameworks/base/core/java/android/print/PrintAttributes.aidl \