Edit in JSFiddle

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 () {
});
<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>
#lastVal {
    width: 5em;
    text-align: left;
    font-family: Courier;
    border: 1 px solid black;
    margin-top: 0px;
    margin-bottom: 1em;
}

#button-holder {
    width: 5em;
    padding-top: 1em;    
}

External resources loaded into this fiddle: