Probably improve behavior around duplicate notifications

Summary:
We're sometimes getting duplicate notifications right now. I think this is because multiple windows are racing and becoming leaders.

Clean this up a little:

  - Fix the `timeoout` typo.
  - Only try to usurp once.
  - Use different usurp and expire delays, so we don't fire them at the exact same time.

Not sure if this'll work or not but it should theoretically be a little cleaner.

Test Plan:
  - Quit Safari, reopened Safari, still saw a fast reconnect to the notification server (this is the goal of usurping).
  - Did normal notification stuff like opening a chat in two windows, got notifications.
  - Hard to reproduce the race for sure, but this at least fixes the outright `timeoout` bug.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D15806

resources/celerity/map.php

@@ -8,7 +8,7 @@
 return array(
   'names' => array(
     'core.pkg.css' => '04a95108',
-    'core.pkg.js' => '37344f3c',
+    'core.pkg.js' => '6972d365',
     'darkconsole.pkg.js' => 'e7393ebb',
     'differential.pkg.css' => '7ba78475',
     'differential.pkg.js' => 'd0cd0df6',
@@ -232,7 +232,7 @@ return array(
     'rsrc/externals/javelin/lib/DOM.js' => '805b806a',
     'rsrc/externals/javelin/lib/History.js' => 'd4505101',
     'rsrc/externals/javelin/lib/JSON.js' => '69adf288',
-    'rsrc/externals/javelin/lib/Leader.js' => 'b4ba945c',
+    'rsrc/externals/javelin/lib/Leader.js' => 'fea0eb47',
     'rsrc/externals/javelin/lib/Mask.js' => '8a41885b',
     'rsrc/externals/javelin/lib/Quicksand.js' => '6b8ef10b',
     'rsrc/externals/javelin/lib/Request.js' => '94b750d2',
@@ -704,7 +704,7 @@ return array(
     'javelin-history' => 'd4505101',
     'javelin-install' => '05270951',
     'javelin-json' => '69adf288',
-    'javelin-leader' => 'b4ba945c',
+    'javelin-leader' => 'fea0eb47',
     'javelin-magical-init' => '3010e992',
     'javelin-mask' => '8a41885b',
     'javelin-quicksand' => '6b8ef10b',
@@ -1772,9 +1772,6 @@ return array(
       'javelin-typeahead-preloaded-source',
       'javelin-util',
     ),
-    'b4ba945c' => array(
-      'javelin-install',
-    ),
     'b59e1e96' => array(
       'javelin-behavior',
       'javelin-stratcom',
@@ -2176,6 +2173,9 @@ return array(
       'javelin-view-visitor',
       'javelin-util',
     ),
+    'fea0eb47' => array(
+      'javelin-install',
+    ),
   ),
   'packages' => array(
     'core.pkg.css' => array(

webroot/rsrc/externals/javelin/lib/Leader.js

@@ -118,6 +118,10 @@ JX.install('Leader', {
       // Read the current leadership lease.
       var lease = self._read();
 
+      // Stagger these delays so that they are unlikely to race one another.
+      var expire_delay = 50;
+      var usurp_delay = 75;
+
       // If the lease is good, we're all set.
       var now = +new Date();
       if (lease.until > now) {
@@ -135,15 +139,17 @@ JX.install('Leader', {
         } else {
 
           // Set a callback to try to become the leader shortly after the
-          // current lease expires. This lets us recover from cases where the
+          // current lease expires. This lets us quickly recover from cases
-          // leader goes missing quickly.
+          // where the leader goes missing.
-          if (self._timeoout) {
+
-            window.clearTimeout(self._timeout);
+          // In particular, this can happen in Safari if you close windows or
-            self._timeout = null;
+          // quit the browser instead of browsing away: the "pagehide" event
+          // does not fire when the leader is simply destroyed, so it does not
+          // evict itself from the throne of power.
+          if (!self._timeout) {
+            var usurp_at = (lease.until - now) + usurp_delay;
+            self._timeout = window.setTimeout(self._usurp, usurp_at);
           }
-          self._timeout = window.setTimeout(
-            self._usurp,
-            (lease.until - now) + 50);
 
           follower_callback();
         }
@@ -174,7 +180,7 @@ JX.install('Leader', {
 
       window.setTimeout(
         JX.bind(null, self._callIf, leader_callback, follower_callback),
-        50);
+        expire_delay);
     },
 
 
@@ -306,6 +312,7 @@ JX.install('Leader', {
     _usurp: function() {
       var self = JX.Leader;
       self.call(JX.bag);
+      self._timeout = null;
     },