Clean up mime package.

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

BUG=
R=kevmoo@google.com

Review URL: https://codereview.chromium.org//292983002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/mime@36543 260f80e4-7a28-3924-810f-c04153c831b5
4 files changed
tree: 92957767f4ce88a0f0bf8521532b05e017c63cf3
  1. lib/
  2. test/
  3. LICENSE
  4. pubspec.yaml