Comment 2 for bug 39136

That would be better than the current situation, but suboptimal in that it would
present the user with a dialog in a number of cases where a dialog should be
avoided (that is, cases where it is overwhelmingly likely that the user would
prefer to see the content in the browser by default).

Isn't browser handling of a type already overridden by the presence of a helper
app entry for that type?