Ensure that mangling is exactly as before

BUG=
R=sigmund@google.com

Review URL: https://chromiumcodereview.appspot.com//18067002
Merge branch 'master' of https://github.com/dart-lang/web-ui into at_host
Bumped to version 0.4.13

BUG=

Review URL: https://chromiumcodereview.appspot.com//18098002
Merge branch 'master' of https://github.com/dart-lang/web-ui into at_host
Enabled @host and tests