adding onChange example code

cookie-bg-picker/popup/bgpicker.js

@@ -59,4 +59,10 @@ reset.onclick = function() {
       name: "bgpicker" 
     })
   });
-}
+}
+
+/* Report cookie changes to the console */
+
+chrome.cookies.onChanged.addListener(function(changeInfo) {
+  console.log('Cookie changed:\n* Cookie: ' + JSON.stringify(changeInfo.cookie) + '\n* Cause: ' + changeInfo.cause + '\n* Removed: ' + changeInfo.removed)
+})

examples.json

@@ -157,7 +157,8 @@
           "Cookie",
           "get",
           "set",
-          "remove"
+          "remove",
+          "onChanged"
         ]
       },
       {