Calling callback if provided for google analytics mock

[niklabh]

URL(s) where the issue occurs

https://www.cars45.com/

Describe the issue

According to google analytics calling ga with a function as the first argument will call that callback with tracker.
https://developers.google.com/analytics/devguides/collection/analyticsjs/command-queue-reference

ga(function(tracker) {
console.log(tracker); // Logs undefined.
});

Adding this behaviour to uBlock

Versions

• Browser/version: [Chrome Version 70.0.3538.102 (Official Build) (64-bit)]
• uBlock Origin version: [uBlock origin 1.17.0]

Notes

Added callback behaviour to mocked ga as well.

[niklabh]

issue #4114

[mapx-]

@gorhill

[gwarser]

@gorhill

Reported here: https://www.reddit.com/r/uBlockOrigin/comments/j3jtaq/ublock_enabled_but_with_all_local_site_blocking/

Clicking on "Get started" button does nothing - should login(?).

ga is called with handleButtonClick:

[gorhill]

Nice, thanks for the investigation. I see a reference about this in the documentation:

Invoking the ga() command queue function by passing it a function will schedule the passed function for execution at the next point in the queue.

I think the safest fix is to call asynchronously the passed function since this is how the real API behaves.

[gorhill]

Err I didn't realize where I was commenting, it's what the pull request was about. Not sure why I was against it since the documentation is clear.

[gwarser]

Yes, and no idea how my test scriptlet was working - my "patch" uses undeclared f variable.

---

Two more fixes and it really seems to work.