Bug 1572029 - Give the tracking protection toggler an accessible label, r=johannh

Differential Revision: https://phabricator.services.mozilla.com/D40996

--HG--
extra : moz-landing-system : lando

browser/base/content/browser-siteProtections.js

@@ -1773,6 +1773,23 @@ var gProtectionsHandler = {
       !currentlyEnabled
     );
 
+    // Give the button an accessible label for screen readers.
+    if (currentlyEnabled) {
+      this._protectionsPopupTPSwitch.setAttribute(
+        "aria-label",
+        gNavigatorBundle.getFormattedString("protections.disableAriaLabel", [
+          host,
+        ])
+      );
+    } else {
+      this._protectionsPopupTPSwitch.setAttribute(
+        "aria-label",
+        gNavigatorBundle.getFormattedString("protections.enableAriaLabel", [
+          host,
+        ])
+      );
+    }
+
     // Update the tooltip of the blocked tracker counter.
     this.maybeUpdateEarliestRecordedDateTooltip();
   },

browser/locales/en-US/chrome/browser/browser.properties

@@ -644,6 +644,16 @@ trackingProtection.icon.noTrackersDetectedTooltip=No trackers known to %S were d
 # Header of the Protections Panel. %S is replaced with the site's hostname.
 protections.header=Protections for %S
 
+# LOCALIZATION NOTE (protections.disableAriaLabel):
+# Text that gets spoken by a screen reader if the button will disable protections.
+# %s is the site's hostname.
+protections.disableAriaLabel=Disable protections for %S
+
+# LOCALIZATION NOTE (protections.enableAriaLabel):
+# Text that gets spoken by a screen reader if the button will enable protections.
+# %s is the site's hostname.
+protections.enableAriaLabel=Enable protections for %S
+
 # Blocking and Not Blocking sub-views in the Protections Panel
 protections.blocking.fingerprinters.title=Fingerprinters Blocked
 protections.blocking.cryptominers.title=Cryptominers Blocked