Missing plugin : Fix null mimetype issue in embed tag

Missing plugin : Fix null mimetype issue in embed tag


In chrome 16,17,18 if you have an embed tag, say flash that has no type information, 
like:

<embed width="100%" name="plugin" src="foo.swf" >

without the type attribute, like  type="application/x-shockwave-flash"

Chrome shows the "missing plugin" element instead of flash.

This uses chrome's knowledge of the mime type instead of just passing webkit's notion of
the mime type which in this case is empty ("").


BUG=108228
TEST=see bug for easy repro case.
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=115468

[cpu_(ooo_6.6-7.5), 2011-12-21 23:30:50]

It is not clear if this is a fallout of a webkit regression but I feel my fix is
safe and protect us from future regression there.

[jam, 2011-12-21 23:34:28]

lgtm