Mozilla userChrome settings to make all extension icons show in greyscale mode

userChrome.css

/* Copyright (c) 2017 Haggai Nuchi
Available for use under the MIT License:
https://opensource.org/licenses/MIT
*/

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

toolbarbutton#alltabs-button {
    -moz-binding: url("userChrome.xml#js");
}

/* disable icons in bookmark bar */
#personal-bookmarks .bookmark-item > .toolbarbutton-icon {display:none!important}

/* greyscale icon for HTTPS icon */
#connection-icon {
  filter: grayscale(100%)
}

/* greyscale icon for container icon */
#userContext-icons {
  filter: grayscale(100%)
}

/* greyscale icon for (active) reader mode icon */
#reader-mode-button {
  filter: grayscale(100%)
}

/* greyscale mode for _ALL_ icons!
source: https://www.reddit.com/r/firefox/comments/77iay2/firefox_beta_is_there_a_way_to_change_icons_color/ */
#navigator-toolbox toolbarbutton {
  filter: grayscale(100%)
}

toolbar#PersonalToolbar .bookmark-item > .toolbarbutton-icon {
	filter: grayscale(100%);
}

userChrome.js

// Copyright (c) 2017 Haggai Nuchi
// Available for use under the MIT License:
// https://opensource.org/licenses/MIT

// Set "useLionFullScreen" in the same way that it's done in
// chrome://browser/content/browser-fullScreenAndPointerLock.js
XPCOMUtils.defineLazyGetter(FullScreen, "useLionFullScreen", function() {
    return false;
});

userChrome.xml

<?xml version="1.0"?>

<!-- Copyright (c) 2017 Haggai Nuchi Available for use under the MIT License: https://opensource.org/licenses/MIT -->

-<bindings xmlns:xbl="http://www.mozilla.org/xbl" xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" xmlns="http://www.mozilla.org/xbl" id="generalBindings">


-<binding id="js" extends="chrome://global/content/bindings/toolbarbutton.xml#toolbarbutton-badged">


-<implementation>


-<constructor>

-<![CDATA[
            function makeRelativePathURI(name) {
              let absolutePath = Components.stack.filename;
              return absolutePath.substring(0, absolutePath.lastIndexOf("/") + 1) + name;
            }
            // The following code executes in the browser context,
            // i.e. chrome://browser/content/browser.xul
            Services.scriptloader.loadSubScript(makeRelativePathURI("userChrome.js"), window);
        ]]>
</constructor>

</implementation>

</binding>

</bindings>