Bug 1861400 - Remove sync if disabled by policy r=fxview-reviewers,nsharpley,kcochrane

Brings the Firefox View behavior in line with what is done in `browser-sync.js`.

Differential Revision: https://phabricator.services.mozilla.com/D205881

browser/components/firefoxview/firefoxview.html

@@ -72,6 +72,7 @@
       >
       </moz-page-nav-button>
       <moz-page-nav-button
+        class="sync-ui-item"
         view="syncedtabs"
         data-l10n-id="firefoxview-synced-tabs-nav"
         iconSrc="chrome://browser/content/firefoxview/view-syncedtabs.svg"
@@ -95,7 +96,10 @@
               <view-recentlyclosed slot="recentlyclosed"></view-recentlyclosed>
             </div>
             <div>
-              <view-syncedtabs slot="syncedtabs"></view-syncedtabs>
+              <view-syncedtabs
+                class="sync-ui-item"
+                slot="syncedtabs"
+              ></view-syncedtabs>
             </div>
           </view-recentbrowsing>
           <view-history name="history" type="page"></view-history>
@@ -104,7 +108,11 @@
             name="recentlyclosed"
             type="page"
           ></view-recentlyclosed>
-          <view-syncedtabs name="syncedtabs" type="page"></view-syncedtabs>
+          <view-syncedtabs
+            class="sync-ui-item"
+            name="syncedtabs"
+            type="page"
+          ></view-syncedtabs>
         </named-deck>
       </div>
     </main>

browser/components/firefoxview/firefoxview.mjs

@@ -80,6 +80,16 @@ async function updateSearchKeyboardShortcut() {
   searchKeyboardShortcut = key.toLocaleLowerCase();
 }
 
+function updateSyncVisibility() {
+  const syncEnabled = Services.prefs.getBoolPref(
+    "identity.fxaccounts.enabled",
+    false
+  );
+  for (const el of document.querySelectorAll(".sync-ui-item")) {
+    el.hidden = !syncEnabled;
+  }
+}
+
 window.addEventListener("DOMContentLoaded", async () => {
   recordEnteredTelemetry();
 
@@ -106,6 +116,7 @@ window.addEventListener("DOMContentLoaded", async () => {
   onViewsDeckViewChange();
   await updateSearchTextboxSize();
   await updateSearchKeyboardShortcut();
+  updateSyncVisibility();
 
   if (Cu.isInAutomation) {
     Services.obs.notifyObservers(null, "firefoxview-entered");
@@ -150,12 +161,17 @@ window.addEventListener(
     document.body.textContent = "";
     topChromeWindow.removeEventListener("command", onCommand);
     Services.obs.removeObserver(onLocalesChanged, "intl:app-locales-changed");
+    Services.prefs.removeObserver(
+      "identity.fxaccounts.enabled",
+      updateSyncVisibility
+    );
   },
   { once: true }
 );
 
 topChromeWindow.addEventListener("command", onCommand);
 Services.obs.addObserver(onLocalesChanged, "intl:app-locales-changed");
+Services.prefs.addObserver("identity.fxaccounts.enabled", updateSyncVisibility);
 
 function onCommand(e) {
   if (document.hidden || !e.target.closest("#contentAreaContextMenu")) {

browser/components/firefoxview/tests/browser/browser_syncedtabs_errors_firefoxview.js

@@ -139,3 +139,36 @@ add_task(async function test_sync_error() {
   });
   await tearDown(sandbox);
 });
+
+add_task(async function test_sync_disabled_by_policy() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["identity.fxaccounts.enabled", false]],
+  });
+  await withFirefoxView({}, async browser => {
+    const { document } = browser.contentWindow;
+    const recentBrowsingSyncedTabs = document.querySelector(
+      "view-syncedtabs[slot=syncedtabs]"
+    );
+    const syncedtabsPageNavButton = document.querySelector(
+      "moz-page-nav-button[view='syncedtabs']"
+    );
+
+    ok(
+      BrowserTestUtils.isHidden(recentBrowsingSyncedTabs),
+      "Synced tabs should not be visible from recent browsing."
+    );
+    ok(
+      BrowserTestUtils.isHidden(syncedtabsPageNavButton),
+      "Synced tabs nav button should not be visible."
+    );
+
+    document.location.assign(`${getFirefoxViewURL()}#syncedtabs`);
+    await TestUtils.waitForTick();
+    is(
+      document.querySelector("moz-page-nav").currentView,
+      "recentbrowsing",
+      "Should not be able to navigate to synced tabs."
+    );
+  });
+  await tearDown();
+});