See summary.
Created attachment 30554 [details] Proposed fix.
Created attachment 30555 [details] Proposed fix.
Comment on attachment 30555 [details] Proposed fix. Looking at MediaPlayer.cpp, it really doesn't matter what we do here. In fact, the cost of getMIMETypeForExtension might not even be worth it. MediaPlayer only calls this function to take a guess at the mime type, which it then uses to help select the media player engine. Chromium only has one engine, so the guessed mime type is not interesting to us. R=me with either the current solution or just returning String() <-- i'd probably just return String().
http://trac.webkit.org/changeset/43981