This article details how you can manage your Chrome permissions while using Click to Call across the web outside of Salesforce.
Users can choose to allow their Chrome extensions to run on click, on a specific set of sites, or on all requested sites. These options are presented to users on the Chrome Extension page (chrome://extensions) as well as in the extension context menu.
What happens if a user chooses to run extensions "on click"?
The extension essentially behaves as though it used the activeTab permission. The extension is granted temporary access to any host the user clicks while the is extension on -- if that host was requested by the extension (and isn't a restricted site, like chrome://settings). When set to run on click, Chrome badges your extension with a circle and drop shadow (see below) to indicate that’s requesting access on a particular site.
What happens if a user chooses to run my extension on specific sites?
Your extension is allowed to run automatically on any sites the user has chosen, and can access the site without further user action. On other sites that your extension requested, but the user did not grant permission to, the behavior is the same as if the user had set the extension to run on click.
What happens if a user chooses to run my extension on all sites?
The extension can automatically access any sites requested in the manifest.