Clean up mime package.

Clean up mime package.

Also speed up default mime-type map, by not using a const map.

BUG=
R=kevmoo@google.com

Committed: https://code.google.com/p/dart/source/detail?r=36543

[Anders Johnsen, 2014-05-20 08:01:48]

This change should not be breaking.

Perf example:

import 'package:mime/mime.dart';

void main() {
  for (int i = 0; i < 1000000; i++) {
    lookupMimeType('baldas/asddf');
  }
}


Before: 5.710s
After: 0.494s

[kevmoo, 2014-05-20 18:55:05]

LGTM w/ a note about a TODO

https://codereview.chromium.org/292983002/diff/1/pkg/mime/lib/src/default_ext...
File pkg/mime/lib/src/default_extension_map.dart (right):

https://codereview.chromium.org/292983002/diff/1/pkg/mime/lib/src/default_ext...
pkg/mime/lib/src/default_extension_map.dart:8: final Map<String, String>
defaultExtensionMap = <String, String>{
I'd put a note here about not using const map w/ a pointer to the bug. That perf
diff is pretty silly

[Anders Johnsen, 2014-05-23 07:07:06]

https://codereview.chromium.org/292983002/diff/1/pkg/mime/lib/src/default_ext...
File pkg/mime/lib/src/default_extension_map.dart (right):

https://codereview.chromium.org/292983002/diff/1/pkg/mime/lib/src/default_ext...
pkg/mime/lib/src/default_extension_map.dart:8: final Map<String, String>
defaultExtensionMap = <String, String>{
On 2014/05/20 18:55:05, kevmoo wrote:
> I'd put a note here about not using const map w/ a pointer to the bug. That
perf
> diff is pretty silly

Done.

[Anders Johnsen, 2014-05-23 07:07:21]

Committed patchset #2 manually as r36543 (presubmit successful).