Add new module-lib APIs for MTS testing

Several android.timezone classes have already been exposed for the
telephony module work, so these tests provide coverage for those.
Additional APIs have been exposed for MTS testing, i.e. to provide
greater confidence that the tzdata module data is correct / is
being read correctly.

Also, small changes to existing code to make them consistent with new
classes. Small docs improvements.

Bug: 147884233
Test: see system/timezone change
Change-Id: I047b29f17a41993f859947a6d6c3685896fe4cb6
diff --git a/api/module-lib-current.txt b/api/module-lib-current.txt
index c8253a0..c657e00 100644
--- a/api/module-lib-current.txt
+++ b/api/module-lib-current.txt
@@ -118,9 +118,31 @@
   }
 
   public final class TimeZoneFinder {
+    method @Nullable public String getIanaVersion();
     method @NonNull public static android.timezone.TimeZoneFinder getInstance();
     method @Nullable public android.timezone.CountryTimeZones lookupCountryTimeZones(@NonNull String);
   }
 
+  public final class TzDataSetVersion {
+    method public static int currentFormatMajorVersion();
+    method public static int currentFormatMinorVersion();
+    method public int getFormatMajorVersion();
+    method public int getFormatMinorVersion();
+    method public int getRevision();
+    method @NonNull public String getRulesVersion();
+    method public static boolean isCompatibleWithThisDevice(android.timezone.TzDataSetVersion);
+    method @NonNull public static android.timezone.TzDataSetVersion read() throws java.io.IOException, android.timezone.TzDataSetVersion.TzDataSetException;
+  }
+
+  public static class TzDataSetVersion.TzDataSetException extends java.lang.Exception {
+    ctor public TzDataSetVersion.TzDataSetException(String);
+    ctor public TzDataSetVersion.TzDataSetException(String, Throwable);
+  }
+
+  public final class ZoneInfoDb {
+    method @NonNull public static android.timezone.ZoneInfoDb getInstance();
+    method @NonNull public String getVersion();
+  }
+
 }