Experimental implementation of SDCH in Chromium

[Jim Roskind]

I've landed an experimental implementation of the SDCH protocol in
Chromium. The changes actually made their way to the Developer and
Beta releases of Google Chrome, which are automatically updated. The
bottom line is that if you're currently running Google Chrome, then
this experimental client side support is in place.

If you're curious to try it out, just use any of the above versions
(including the standard "Google Chrome" beta release) and add the
command line option:

-enable-sdch

If you just want to experiment with a specific server/host/domain that
is supporting the corresponding server side feature, then use the
specific command line option:

-enable-sdch=host.your.domain

With that restriction, sdch support will be restricted to you to
transactions with the indicated host.

The easiest way to add that command line option so that it is always
run is (on Windows) by editing the properties for the Google Chrome
startup icon, and adding the above text after the name of the
executable in the "Target" field. For example, this is how my Target
field currently reads:

"C:\Documents and Settings\jar\Local Settings\Application Data\Google
\Chrome\Application\chrome.exe" --enable-sdch

This implementation uses the excellent underlying open source code
from Open-Vcdiff. http://code.google.com/p/open-vcdiff/ More info on
it is available in the Google Group http://groups.google.com/group/open-vcdiff

Caveat: If you experiment with this feature, you'll of course need a
server that provides the compression. Also note that the dictionary
download is currently done about 15 seconds after a server tells the
browser about the dictionary's availability.

Enjoy,

Jim