Created a cookie tracker in trackers.js, and a test for it in tests/unit/test_cookie_store.js.

services/sync/modules/engines.js

@@ -1029,6 +1029,13 @@ CookieEngine.prototype = {
     if (!this.__store)
       this.__store = new CookieStore();
     return this.__store;
+  },
+
+  __tracker: null,
+  get _tracker() {
+    if (!this.__tracker)
+      this.__tracker = new CookieTracker();
+    return this.__tracker;
   }
 };
 CookieEngine.prototype.__proto__ = new Engine();
@@ -1111,4 +1118,4 @@ FormEngine.prototype = {
     return this.__tracker;
   }
 };
-FormEngine.prototype.__proto__ = new Engine();
+FormEngine.prototype.__proto__ = new Engine();

services/sync/modules/trackers.js

@@ -35,7 +35,7 @@
  * ***** END LICENSE BLOCK ***** */
 
 const EXPORTED_SYMBOLS = ['Tracker', 'BookmarksTracker', 'HistoryTracker',
-                          'FormsTracker'];
+                          'FormsTracker', 'CookieTracker'];
 
 const Cc = Components.classes;
 const Ci = Components.interfaces;
@@ -197,6 +197,41 @@ HistoryTracker.prototype = {
 }
 HistoryTracker.prototype.__proto__ = new Tracker();
 
+function CookieTracker() {
+  this._init();
+}
+CookieTracker.prototype = {
+  _logName: "CookieTracker",
+
+  _init: function CT__init() {
+    this._log = Log4Moz.Service.getLogger("Service." + this._logName);
+    this._score = 0;
+    /* cookieService can't register observers, but what we CAN do is
+       register a general observer with the global observerService
+       to watch for the 'cookie-changed' message. */
+    let observerService = Cc["@mozilla.org/observer-service;1"].
+            getService(Ci.nsIObserverService);
+    observerService.addObserver( this, 'cookie-changed', false );
+  },
+
+  // implement observe method to satisfy nsIObserver interface
+  observe: function ( aSubject, aTopic, aData ) {
+    /* This gets called when any cookie is added, changed, or removed.
+       aData will contain a string "added", "changed", etc. to tell us which,
+       but for now we can treat them all the same. aSubject is the new
+       cookie object itself. */
+    var newCookie = aSubject.QueryInterface( Ci.nsICookie2 );
+    if ( newCookie ) {
+      if ( !newCookie.isSession ) {
+	/* Any modification to a persistent cookie is worth
+	   10 points out of 100.  Ignore session cookies. */
+	this._score += 10;
+      }
+    }
+  }
+}
+CookieTracker.prototype.__proto__ = new Tracker();
+
 function FormsTracker() {
   this._init();
 }

services/sync/tests/unit/test_cookie_store.js

@@ -83,6 +83,44 @@ FakeCookieManager.prototype = {
   }
 };
 
+function sub_test_cookie_tracker() {
+  Components.utils.import("resource://weave/trackers.js");
+
+  var ct = new CookieTracker();
+
+  // gonna have to use the real cookie manager here...
+  var cookieManager = Cc["@mozilla.org/cookiemanager;1"].
+                             getService(Ci.nsICookieManager2);
+  var d = new Date();
+  d.setDate( d.getDate() + 1 );
+  cookieManager.add( "www.evilbrainjono.net",
+                     "/blog/",
+                     "comments",
+                     "on",
+                     false,
+                     true,
+                     false,
+                     d.getTime() );
+  cookieManager.add( "www.evilbrainjono.net",
+                     "/comic/",
+                     "lang",
+                     "jp",
+                     false,
+                     true,
+                     false,
+                     d.getTime() );
+  cookieManager.add( "www.evilbrainjono.net",
+                     "/blog/",
+                     "comments",
+                     "off",
+                     false,
+                     true,
+                     true, // session
+                     d.getTime() );
+  // score is 10 per cookie changed, but we should be ignoring the
+  // session cookie, so we should be at 20 now.
+  do_check_eq( ct.score, 20 );
+};
 
 function run_test() {
   /* Set a persistent cookie and a non-persistent cookie
@@ -110,4 +148,5 @@ function run_test() {
   var jsonGuids = [ guid for ( guid in json ) ];
   do_check_eq( jsonGuids.length, 1 );
   do_check_eq( jsonGuids[0], "evilbrainjono.net:/:login" );
+  sub_test_cookie_tracker();
 }