Let CSSImportRule construct MediaLists by passing the parent style sheet like everyone else.
Created attachment 117884 [details]
Attachment 117884 [details] did not pass style-queue:
Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebCore/ChangeLog', u'Source/WebCor..." exit_code: 1
Source/WebCore/ChangeLog:1: ChangeLog entry has no bug number [changelog/bugnumber] 
Total errors found: 1 in 2 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Committed r102152: <http://trac.webkit.org/changeset/102152>