Setting Non-Chrome Window Size in Protractor Config For Selenium Tests

Question

So for Chrome, my understanding is that the following allows Protractor to decide the size of the window:

exports.config = {
    ...

    capabilities: {
        browserName: 'chrome',
        chromeOptions: {
            args: ['--window-size=1440,900', '-window-position=0,0']
        },
    },

    ...
}

What I am attempting to do is apply a similar method to other browsers, specifically Firefox and Internet Explorer. I am specifically trying to avoid having the browser resize itself as part of the test process. I decided to start my efforts with Firefox.

Searching for information in the protractor forums led me here which recommends setting the getMultiCapabilities property of the exports.config object to a promise containing an encoded instance of firefox-profile. Attempting to implement that solution caused any attempts to run my test suite to launch Chrome windows instead of Firefox.

As near as I can tell, the demo project in question is simply out of date. Another Stack Overflow post led me towards trying this:

var FirefoxProfile = require('firefox-profile');
exports.config = {
    ...

    capabilities: firefoxCapabilities(),

    ...
}

function firefoxCapabilities() {
    var firefoxProfile = new FirefoxProfile();

    return {
        browserName: 'firefox',
        maxSessions: 1,
        firefox_profile : firefoxProfile,
    };
}

This almost, ALMOST seems to work. It does at the very least launch Firefox, unlike the example in the demo project. Unfortunately, as per this it seems as though I am supposed to use selenium-webdriver/firefox instead of firefox-profile. Okay, all well and good, I just have to install another package since require can't find selenium-webdriver/firefox; oh wait, that should already be available? Then it's getting complex, and I haven't even seen something to lead me to believe that creating my own Firefox profile will even let me set the window dimensions as I wish.

Changing tack, I found this (specifically, the answer by Martin Sznapka) which seems to be suggesting a much simpler solution: using the onPrepare property to tell the driver what dimensions it should be using. That said, IntelliJ is informing me that onPrepare is an unused function and, when I forge on and try to implement the solution anyway, nothing seems to change. Variations don't seem to help.

So at this point I have spent more than a few hours trying simply to have protractor define the dimensions of the window as it does so easily for Chrome. Between out-of-date demos, extra packages, and solutions that seem completely ineffective, I find myself wondering if I am even on the right track.

Any help or point-in-the-right-direction would be greatly appreciated.

Edit: As per request, here is my full exports.config object. This launches Firefox but does not appear to have any effect on the window size.

exports.config = {
    baseUrl: 'http://localhost:8080/',
    directConnect: true,
    framework: 'jasmine',
    capabilities: {
        browserName: 'firefox',
        maxSessions: 1,
    },
    // Options to be passed to Jasmine.
    jasmineNodeOpts: {
        defaultTimeoutInterval: 60000
    },
    //Ensures that user is signed in before running tests
    onPrepare: function () {
        var disableNgAnimate = function () {
            angular.module('disableNgAnimate', []).run([
                '$animate', function ($animate) {
                    $animate.enabled(false);
                }
            ]);
        };
        browser.addMockModule('disableNgAnimate', disableNgAnimate);

        beforeEach(function () {
            browser.ignoreSynchronization = true; // prevents waiting on angular until timing out.
            browser.driver.manage().window().setSize(300, 300);
        });
    },
    seleniumAddress: 'http://localhost:4444/wd/hub',
    specs: ['**/*.spec.js'],
    suites: {
        demo: 'demo/demo.spec.js',
        index: 'index/index.spec.js',
    }
};