Reviewed by Alexey Proskuryakov.

        Use a media file inside of LayoutTests/http/ so a cgi isn't necessary to load 
        it. Fixes a test failure introduced in r42533.

        * http/tests/resources/silence.mpg: Added.
        * http/tests/security/local-video-source-from-remote-expected.txt:
        * http/tests/security/local-video-source-from-remote.html: change the
        remote url, update a comment.
        * http/tests/security/resources/load-media.cgi: Removed.


git-svn-id: svn://svn.chromium.org/blink/trunk@42543 bbb929c8-8fbe-4397-9dbb-9b2b20218538