Bug 1976952 - Change Taskbar Tabs page action visibility as the pref changes. r=nrishel

Differential Revision: https://phabricator.services.mozilla.com/D257056

Author: dmcintosh-moz

browser/components/taskbartabs/TaskbarTabsPageAction.sys.mjs

@@ -35,16 +35,10 @@ export const TaskbarTabsPageAction = {
    * @param {DOMWindow} aWindow - The browser window.
    */
   init(aWindow) {
-    let taskbarTabsEnabled = lazy.TaskbarTabsUtils.isEnabled();
     let isPopupWindow = !aWindow.toolbar.visible;
     let isPrivate = lazy.PrivateBrowsingUtils.isWindowPrivate(aWindow);
 
-    if (
-      !taskbarTabsEnabled ||
-      isPopupWindow ||
-      isPrivate ||
-      AppConstants.platform != "win"
-    ) {
+    if (isPopupWindow || isPrivate || AppConstants.platform != "win") {
       lazy.logConsole.info("Not initializing Taskbar Tabs Page Action.");
       return;
     }
@@ -131,7 +125,8 @@ export const TaskbarTabsPageAction = {
  * @param {Element} aElement - The element that makes up the page action.
  */
 function initVisibilityChanges(aWindow, aElement) {
-  const shouldHide = aLocation => !aLocation.scheme.startsWith("http");
+  const shouldHide = aLocation =>
+    !(aLocation.scheme.startsWith("http") && lazy.TaskbarTabsUtils.isEnabled());
   aElement.hidden = shouldHide(aWindow.gBrowser.currentURI);
 
   aWindow.gBrowser.addProgressListener({
@@ -141,4 +136,13 @@ function initVisibilityChanges(aWindow, aElement) {
       }
     },
   });
+
+  const observer = () => {
+    aElement.hidden = shouldHide(aWindow.gBrowser.currentURI);
+  };
+
+  Services.prefs.addObserver("browser.taskbarTabs.enabled", observer);
+  aWindow.addEventListener("unload", function () {
+    Services.prefs.removeObserver("browser.taskbarTabs.enabled", observer);
+  });
 }

browser/components/taskbartabs/test/browser/browser_taskbarTabs_pageAction.js

@@ -301,3 +301,22 @@ add_task(async function testIframeNavigationIsIgnored() {
 function getURIScheme(uri) {
   return Services.io.newURI(uri).scheme;
 }
+
+add_task(async function testPrefIsMonitored() {
+  const element = document.getElementById("taskbar-tabs-button");
+
+  await BrowserTestUtils.withNewTab(BASE_URL, async () => {
+    ok(!element.hidden, "Page action starts as visible");
+    await testVisibilityChange(BASE_URL, HIDDEN_URI, true, false);
+
+    await SpecialPowers.pushPrefEnv({
+      set: [["browser.taskbarTabs.enabled", false]],
+    });
+    ok(element.hidden, "Page action becomes invisible");
+    await testVisibilityChange(BASE_URL, HIDDEN_URI, false, false);
+
+    await SpecialPowers.popPrefEnv();
+    ok(!element.hidden, "Page action becomes visible again");
+    await testVisibilityChange(BASE_URL, HIDDEN_URI, true, false);
+  });
+});