Windows: Fix 64-bit compile errors (issue #1184).

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk/cef3@1576 5089003a-bbd8-11dd-ad1f-f1f9622dbc98
Add a CefGetMimeType function for retrieving the mime type of a file extension (issue #1098).

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk/cef3@1577 5089003a-bbd8-11dd-ad1f-f1f9622dbc98