Bug 1321865 - Enable IntersectionObserver. r=smaug

--HG--
extra : rebase_source : 9a72845f93fc4a11f0fda0b30b936dae2df303f6
extra : histedit_source : a153d18b9cfa85afd1d2e41e36995e4b1a9b8b75

modules/libpref/init/all.js

@@ -5553,4 +5553,4 @@ pref("prompts.authentication_dialog_abuse_limit", 3);
 // Enable the Storage management in about:preferences and persistent-storage permission request
 // To enable the DOM implementation, turn on "dom.storageManager.enabled"
 pref("browser.storageManager.enabled", false);
-pref("dom.IntersectionObserver.enabled", false);
+pref("dom.IntersectionObserver.enabled", true);