Best way to control firefox via webdriver - firefox

Question

I need to control Firefox browser via webdriver. Note, I'm not trying to control page elements (i.e. find element, click, get text, etc); rather I need access to Firefox's profiler and force gc (i.e. I need firefox's Chrome Authority and sdk). For context, I'm creating a micro benchmark framework, not running a normal webdriver test.
Obviously raw webdriver won't work, so what I've been trying to do is
1) Create a firefox extension/add-on that does what I need: i.e.
var customActions = function() {
console.log('calling customActions.')
// I need to access chrome authority:
var {Cc,Ci,Cu} = require("chrome");
Cc["#mozilla.org/tools/profiler;1"].getService(Ci.nsIProfiler);
Cu.forceGC();
var file = require('sdk/io/file');
// And do some writes:
var textWriter = file.open('a/local/path.txt', 'w');
textWriter.write('sample data');
textWriter.close();
console.log('called customActions.')
};
2) Expose my customActions function to a page:
var mod = require("sdk/page-mod");
var data = require("sdk/self").data;
mod.PageMod({
include: ['*'],
contentScriptFile: data.url("myscript.js"),
onAttach: function(worker) {
worker.port.on('callCustomActions', function() {
customActions();
});
}
});
and in myscript.js:
exportFunction(function() {
self.port.emit('callCustomActions');
}, unsafeWindow, {defineAs: "callCustomActions"});
3) Load the xpi during my webdriver test, and call out to global function callCustomActions
So two questions about this process.
1) This entire process is very roundabout. Is there a better practice for talking to a firefox extension via webdriver?
2) My current solution isn't working well. If I run my extension via cfx run directly (without webdriver) it works as expected. However, neither the sdk nor chrome authority do anything when running via webdriver.
By the way, I know my function is being called because the log line "calling customActions." and "called customActions." both do print.
Maybe there are some firefox preferences that I need to set but haven't?

Answer 1

It may be that you do not need the add-on at all. Mozilla uses Marionette for test automation of Firefox OS amongst other things:
Marionette is an automation driver for Mozilla's Gecko engine. It can
remotely control either the UI or the internal JavaScript of a Gecko
platform, such as Firefox or Firefox OS. It can control both the
chrome (i.e. menus and functions) or the content (the webpage loaded
inside the browsing context), giving a high level of control and
ability to replicate user actions. In addition to performing actions
on the browser, Marionette can also read the properties and attributes
of the DOM.
If this sounds similar to Selenium/WebDriver then you're correct!
Marionette shares much of the same ethos and API as
Selenium/WebDriver, with additional commands to interact with Gecko's
chrome interface. Its goal is to replicate what Selenium does for web
content: to enable the tester to have the ability to send commands to
remotely control a user agent.