Modified the file extension filters for downloads to add some extensions to a default list for all platforms. Also added a few previously overlooked extensions for various platforms.

      BUG=59817
TEST=None
Review URL: http://codereview.chromium.org/3899002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@63158 0039d316-1c4b-4281-b951-d872f2087c98