Bug 1828966 - Ensure Pin to Toolbar context menu item shows the correct state when opening the context menu. r=mconley

I could only reproduce on macOS but it is indeed a valid bug. I noticed
that moving the `await` code at the bottom of the function fixed it but
that didn't sound too great.

I decided to propose this patch instead, and I made sure that we
wouldn't hit a similar problem with the "disabled" state of the remove
button. Apparently, that still works as expected (on macOS).

I am not quite sure how to cover that with a test, though, because we
have test coverage for the attributes and the HTML markup is correctly
updated. For example, I could see the correct `checked` attribute in the
HTML (in the devtools) with the wrong context menu item state rendered,
sigh. This likely means the race is at a lower level (cocoa?).

Differential Revision: https://phabricator.services.mozilla.com/D176416

UltraBlame original commit: 123d6c05b43fbf76d56f9326a177a1851610133d

Author: marco-c

browser/base/content/browser-addons.js

@@ -1592,7 +1592,7 @@ var gUnifiedExtensions = {
     window.dispatchEvent(new CustomEvent("UnifiedExtensionsTogglePanel"));
   },
 
-  async updateContextMenu(menu, event) {
+  updateContextMenu(menu, event) {
 
 
 
@@ -1601,7 +1601,6 @@ var gUnifiedExtensions = {
     }
 
     const id = this._getExtensionId(menu);
-    const addon = await AddonManager.getAddonByID(id);
     const widgetId = this._getWidgetId(menu);
     const forBrowserAction = !!widgetId;
 
@@ -1621,17 +1620,22 @@ var gUnifiedExtensions = {
     menuSeparator.hidden = !forBrowserAction;
     pinButton.hidden = !forBrowserAction;
 
+    reportButton.hidden = !gAddonAbuseReportEnabled;
+    
+    
+    
+    AddonManager.getAddonByID(id).then(addon => {
+      removeButton.disabled = !(
+        addon.permissions & AddonManager.PERM_CAN_UNINSTALL
+      );
+    });
+
     if (forBrowserAction) {
       let area = CustomizableUI.getPlacementOfWidget(widgetId).area;
       let inToolbar = area != CustomizableUI.AREA_ADDONS;
       pinButton.setAttribute("checked", inToolbar);
     }
 
-    reportButton.hidden = !gAddonAbuseReportEnabled;
-    removeButton.disabled = !(
-      addon.permissions & AddonManager.PERM_CAN_UNINSTALL
-    );
-
     ExtensionsUI.originControlsMenu(menu, id);
 
     const browserAction = this.browserActionFor(WebExtensionPolicy.getByID(id));