Document date format initialization better and make it possible to use en_US dates without it

Document date format initialization better and make it possible to use en_US dates without it

dartbug.com/6567
Committed: https://code.google.com/p/dart/source/detail?r=16582

[Alan Knight, 2012-12-21 21:55:20]

This provides better documentation of the need to initialize things. And while I
was at it, the main use case people have complained about is just wanting to do
basic date formatting without a locale, so made the uninitialized locale data
have a copy of the en_US data so it's able to format things in that format
without any initialization.

[Emily Fortuna, 2012-12-21 23:30:23]

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/lib/date_format.dart
File pkg/intl/lib/date_format.dart (right):

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/lib/date_format.d...
pkg/intl/lib/date_format.dart:8: // feedback on appropriateness.
danke schön :-)

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/test/date_time_fo...
File pkg/intl/test/date_time_format_test_core.dart (right):

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/test/date_time_fo...
pkg/intl/test/date_time_format_test_core.dart:231: testLocale("en_US", English,
aDate);
can we pull this one out  of the if block, since we know en_US should always be
there?

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/test/date_time_fo...
pkg/intl/test/date_time_format_test_core.dart:281: testLocale('de_at', Austrian,
aDate);
accidental indentation?

[Alan Knight, 2012-12-21 23:34:25]

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/test/date_time_fo...
File pkg/intl/test/date_time_format_test_core.dart (right):

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/test/date_time_fo...
pkg/intl/test/date_time_format_test_core.dart:231: testLocale("en_US", English,
aDate);
On 2012/12/21 23:30:23, Emily Fortuna wrote:
> can we pull this one out  of the if block, since we know en_US should always
be
> there?
> 

Done.

https://codereview.chromium.org/11669013/diff/3001/pkg/intl/test/date_time_fo...
pkg/intl/test/date_time_format_test_core.dart:281: testLocale('de_at', Austrian,
aDate);
On 2012/12/21 23:30:23, Emily Fortuna wrote:
> accidental indentation?

Done.

[Emily Fortuna, 2012-12-21 23:34:52]

lgtm