FYI, I put together a JSFiddle of this using the $cookieStore, two controllers, a $rootScope, and AngularjS 1.0.6. It's on JSFifddle as http://jsfiddle.net/krimple/9dSb2/ as a base if you're messing around with this...
The gist of it is:
Javascript
var myApp = angular.module('myApp', ['ngCookies']);
myApp.controller('CookieCtrl', function ($scope, $rootScope, $cookieStore) {
$scope.bump = function () {
var lastVal = $cookieStore.get('lastValue');
if (!lastVal) {
$rootScope.lastVal = 1;
} else {
$rootScope.lastVal = lastVal + 1;
}
$cookieStore.put('lastValue', $rootScope.lastVal);
}
});
myApp.controller('ShowerCtrl', function () {
});
HTML
<div ng-app="myApp">
<div id="lastVal" ng-controller="ShowerCtrl">{{ lastVal }}</div>
<div id="button-holder" ng-controller="CookieCtrl">
<button ng-click="bump()">Bump!</button>
</div>
</div>