Knowing how I would have written the call tracking library, I guessed that there was probably some way to debug or test code in this scenario. I carefully read through the minified code, utilizing the Chrome Developer Tools and the Pretty Print functionality. I even set a few break points to confirm what I felt was a way to trigger a debugger.
So what is the [workaround]?
The secret is to append #goog-wcm-debug to the Query String of the URL and reload the window. That will load a hidden DIV into the DOM. It’s hidden because the style is set to display: none. There are also two buttons: Retry and Force. I knew that the Force button was the one I needed. See the screen shot below:
To unhide the DIV and the buttons is a simple matter of changing the style in the Styles Tab. See the screen-shot below:
When you click on the Force Button it returns a default test number from the Google library. You are then able to verify if your code works and actually replaces the numbers you want.
And voila! Problem solved!