[threeten-dev] Review request: JapaneseChronology/JapaneseDate fixes

[Masayoshi Okutsu]

Hi,

I've fixed various JapaneseChronology and JapaneseDate implementation 
bugs, mostly missing or incorrect validations.

Here's the webrev.
http://cr.openjdk.java.net/~okutsu/310/japanesechrono/webrev.00/

One question is, why 0 and -10 of Heisei are considered as valid 
yearOfEra values in TCKJapaneseChronology.java? Please let me know if 
prolepticYear(era, yearOfEra) should rather be lenient (in the current era).

Thanks,
Masayoshi