Merge 115468 - Missing plugin : Fix null mimetype issue in embed tag

Merge 115468 - 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.
Review URL: http://codereview.chromium.org/9016030

TBR=cpu@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=115677