Bug 1325464 - Enable object-shorthand rule and run 'mach eslint --fix' with the rule enabled. r=MattN

MozReview-Commit-ID: 8WoGr8i6oCR

toolkit/components/privatebrowsing/PrivateBrowsingTrackingProtectionWhitelist.js

@@ -58,7 +58,7 @@ PrivateBrowsingTrackingProtectionWhitelist.prototype = {
     return this._allowlist.indexOf(uri.spec) !== -1;
   },
 
-  observe: function(subject, topic, data) {
+  observe(subject, topic, data) {
     if (topic == "last-pb-context-exited") {
       this._allowlist = [];
     }