This fixes a regression introduced by my fix for http://code.google.com/p/chromium/issues/detail?id=2846 (Revision 3262).
This fixes a regression introduced by my fix for http://code.google.com/p/chromium/issues/detail?id=2846 (Revision 3262).

The one to one mapping between mime types and supported extensions, which 
enables us to look up a plugin based on a URL extension regressed as a result
of the above change.

R=jam


Review URL: http://codereview.chromium.org/7272

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@3300 0039d316-1c4b-4281-b951-d872f2087c98

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