Asking for consent - Piwik

[jayhaluska]

Hey guys,

I just realized that there is no way to use the "Ask for consent" feature of Matomo (Piwik). This is relevant because of the new GDPR in europe. I'm about to create a pull request for this one, but I want to hear your opinions on my implementation idea.

I want to introduce a PIWIK_ASK_FOR_CONSENT variable, like PIWIK_DISABLE_COOKIES.
To make it easy for the user of the consent functionality to integrate the request for consent, I wrote event listeners which are triggered on click and are attached to DOM elements with the following id's:

piwik_deny_consent
piwik_give_consent

What do you think? Do you see any problems with this kind of implementation?