Download and install the latest version of Chromium for Mac.

gistfile1.sh

#!/bin/sh
# Install the latest Chromium mac nightly build, but only
# if it's different from the currently installed version.
set -e

build_url="http://commondatastorage.googleapis.com/chromium-browser-snapshots/Mac"
install_dir="/Applications/Chromium.app"

# determine the currently installed chromium build number
current=0
test -d "$install_dir" && current=$(
    cat "$install_dir/Contents/Info.plist"             |
    grep -A1 "<key>SCMRevision</key>"                  |
    tail -n 1                                          |
    sed 's/.*<string>\(.*\)<\/string>.*/\1/'
)

# most recent version build available from google
latest=$(curl -s "$build_url/LAST_CHANGE")
if [ "$current" != "$latest" ]; then
    echo "==> Fetching Chromium build $latest" 1>&2

    # setup a temp dir to do some work
    tmpdir="/tmp/$(basename $0)-$latest"
    trap "cd / && rm -rf $tmpdir" EXIT
    mkdir -p "$tmpdir"
    cd "$tmpdir"

    # fetch it
    curl -# -O "$build_url/$latest/chrome-mac.zip"

    printf "\n==> Extracting ...\n" 1>&2
    unzip -q chrome-mac.zip

    # remove the previous backup
    backup_dir="$(dirname $install_dir)/.$(basename $install_dir)"
    rm -rf "$backup_dir"

    # backup the currently installed Chromium.app
    test -d "$install_dir" &&
    mv "$install_dir" "$backup_dir"

    # move the new one into place
    mv "chrome-mac/Chromium.app" "$install_dir"
    echo "==> Chromium upgraded to build $latest (from $current)."
else
    echo "==> You already have build $latest." 1>&2
fi