Re-start A/B/C test on 'Start now' buttons

This commit reverts #2337.
We ran a multivariate test for 'start now' buttons on 3 start pages in early March 2016. We want to run the test again to increase our confidence that the improvement trends shown in the original test are valid, with the same options winning and with a similar scale if difference.

app/assets/javascripts/smart-answers.js

@@ -1,3 +1,5 @@
+//= require start-now-button-abc-tests
+
 function browserSupportsHtml5HistoryApi() {
   return !! (history && history.replaceState && history.pushState);
 }

app/assets/javascripts/start-now-button-abc-tests.js

@@ -0,0 +1,45 @@
+//= require govuk/multivariate-test
+
+$(function(){
+  if(window.location.href.indexOf("/overseas-passports") > -1) {
+    new GOVUK.MultivariateTest({
+      el: '.get-started a',
+      name: 'startButton_osPassport_201602',
+      customDimensionIndex: 13,
+      contentExperimentId: 'egf8SiUzQJmsUuEIbxkCRw',
+      cohorts: {
+        original: { callback: function() {}, variantId: 0 },
+        getApplicationInfo: { html: 'Get application information', variantId: 1 },
+        next: { html: 'Next', variantId: 2 }
+      }
+    });
+  }
+
+  if(window.location.href.indexOf("/calculate-your-child-maintenance") > -1) {
+    new GOVUK.MultivariateTest({
+      el: '.get-started a',
+      name: 'startButton_calcChildM_201602',
+      customDimensionIndex: 13,
+      contentExperimentId: 'u0MzUmYRRzmb5mchoGp9Fw',
+      cohorts: {
+        original: { callback: function() {}, variantId: 0 },
+        calculate: { html: 'Calculate', variantId: 1 },
+        estimateChildMaintenance: { html: 'Estimate your child maintenance', variantId: 2 }
+      }
+    });
+  }
+
+  if(window.location.href.indexOf("/marriage-abroad") > -1) {
+    new GOVUK.MultivariateTest({
+      el: '.get-started a',
+      name: 'startButton_marriageAbroad_201602',
+      customDimensionIndex: 13,
+      contentExperimentId: 'Xk_FTKgiTwikoIH0fzPklw',
+      cohorts: {
+        original: { callback: function() {}, variantId: 0 },
+        findOutHow: { html: 'Find out how', variantId: 1 },
+        getMoreInfo: { html: 'Get more information', variantId: 2 }
+      }
+    });
+  }
+});