Schematize Crypto state system property

Properties accessed across partitions are now schematized and will
become APIs to make explicit interfaces among partitions.

Bug: 117924132
Test: m -j
Change-Id: I957a8e37a88f7bb6d5007a36c02952d3539580fe

src/com/android/settings/development/FileEncryptionPreferenceController.java

@@ -63,7 +63,8 @@ public class FileEncryptionPreferenceController extends DeveloperOptionsPreferen
 
     @Override
     public void updateState(Preference preference) {
-        if (!TextUtils.equals("file", CryptoProperties.type().orElse("none"))) {
+        if (CryptoProperties.type().orElse(CryptoProperties.type_values.NONE) !=
+            CryptoProperties.type_values.FILE) {
             return;
         }