Don't override application/octet-stream MIME type.

When enumerating candidate plug-ins for handling a document,
PluginList::GetPluginInfoArray() attemps to match the MIME type of the
document, and then matches the file type based on the URL. Matching by
file type is done if the MIME type of the document is either empty or if
is application/octet-stream.

This change disallows plugin matching based on file type if the MIME
type is application/octet-stream. This will, for example, prevent
http://example.com/foo.pdf from being associated with the PDF plug-in if
it is served with a MIME type of application/octet-stream.

As a side-effect, this brings the BufferedResourceHandler's decision of
whether a resource should be rendered or downloaded closer in line with
Blink's.

BUG=104331

Review URL: https://chromiumcodereview.appspot.com/18364005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@213119 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed