Bug 1740300 - Do not send handoff from Private Browsing Mode. r=mstange

Differential Revision: https://phabricator.services.mozilla.com/D130772

browser/base/content/browser.js

@@ -5589,9 +5589,15 @@ var XULBrowserWindow = {
       return;
     }
 
+    let url = uri.spec;
+    if (PrivateBrowsingUtils.isWindowPrivate(win)) {
+      // Passing an empty string to MacUserActivityUpdater will invalidate the
+      // current user activity.
+      url = "";
+    }
     let baseWin = win.docShell.treeOwner.QueryInterface(Ci.nsIBaseWindow);
     MacUserActivityUpdater.updateLocation(
-      uri.spec,
+      url,
       win.gBrowser.contentTitle,
       baseWin
     );

widget/cocoa/nsMacUserActivityUpdater.mm

@@ -23,7 +23,8 @@ nsMacUserActivityUpdater::UpdateLocation(const nsAString& aPageUrl, const nsAStr
   }
 
   NSURL* pageUrl = nsCocoaUtils::ToNSURL(aPageUrl);
-  if (![pageUrl.scheme isEqualToString:@"https"] && ![pageUrl.scheme isEqualToString:@"http"]) {
+  if (!pageUrl ||
+      (![pageUrl.scheme isEqualToString:@"https"] && ![pageUrl.scheme isEqualToString:@"http"])) {
     [cocoaWin.userActivity invalidate];
     return NS_OK;
   }