[benchmark.html] Recreate data also when size decreases
[benchmark.html] Recreate data also when size decreases

R=yhirano@chromium.org

Review URL: https://codereview.appspot.com/101520044
google/pywebsocket,GoogleChromeLabs/pywebsocket3,googlearchive/pywebsocket,googlearchive/pywebsocket,google/pywebsocket,GoogleChromeLabs/pywebsocket3,googlearchive/pywebsocket,GoogleChromeLabs/pywebsocket3,google/pywebsocket