Make the http server built into the selenium tester return 404 for most unknown urls.
Make the http server built into the selenium tester return 404 for most unknown urls.

Review URL: http://codereview.chromium.org/1587010

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@1938 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client