MacOS – How to make/receive Google Voice calls in Mountain Lion

You can also click elements with JavaScript:

tell application "Google Chrome" to tell active tab of window 1
    execute javascript "document.getElementById('chrome-web-store-title').click()"
    --execute javascript "document.querySelectorAll('.tile-grid .most-visited')[3].click()"
end tell

Focusing an existing tab by URL:

tell application "Google Chrome"
    repeat with w in windows
        set i to 1
        repeat with t in tabs of w
            if URL of t starts with "https://mail.google" then
                set active tab index of w to i
                set index of w to 1
                return
            end if
            set i to i + 1
        end repeat
    end repeat
end tell

Apple now includes the xcode-select binary in OS X itself, so you have a one line solution that presents a graphical authorization window and then downloads and installs the current version of the tools.

xcode-select --install