Clean up junk in content sniffing mock-http-headers.

R=deanm

Review URL: http://codereview.chromium.org/13166

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6423 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/data/content-sniffer-test0.html.mock-http-headers

 HTTP/1.1 200 OK
 Content-Length: 121
-Date: Mon, 13 Nov 2006 21:38:09 GMT
-Expires: Tue, 14 Nov 2006 19:23:58 GMT

chrome/test/data/content-sniffer-test1.html.mock-http-headers

 HTTP/1.1 200 OK
 Content-Type: text/plain; charset=utf-8
 Content-Length: 125
-Date: Mon, 13 Nov 2006 21:38:09 GMT
-Expires: Tue, 14 Nov 2006 19:23:58 GMT

chrome/test/data/content-sniffer-test2.html.mock-http-headers

 HTTP/1.1 200 OK
 Content-Type: image/gif
 Content-Length: 142
-Date: Mon, 13 Nov 2006 21:38:09 GMT
-Expires: Tue, 14 Nov 2006 19:23:58 GMT

chrome/test/data/content-sniffer-test3-frame.txt.mock-http-headers

 HTTP/1.1 200 OK
 Content-Length: 0
-Date: Tue, 22 Apr 2008 22:56:55 GMT

chrome/test/data/content-sniffer-test3.html.mock-http-headers

 HTTP/1.1 200 OK
-Content-Length: 487
-Date: Tue, 22 Apr 2008 22:56:55 GMT
-Content-Length: 333
+Content-Length: 472
 Content-Type: text/html

chrome/test/data/nosniff-test.html.mock-http-headers

 HTTP/1.1 200 OK
 Content-Length: 111
 X-Content-Type-Options: nosniff
-Date: Mon, 13 Nov 2006 21:38:09 GMT
-Expires: Tue, 14 Nov 2006 19:23:58 GMT