[NTP4] Experiment for adding Chrome Web Store link to footer.

chrome/browser/resources/ntp4/new_tab.js

Index: chrome/browser/resources/ntp4/new_tab.js
diff --git a/chrome/browser/resources/ntp4/new_tab.js b/chrome/browser/resources/ntp4/new_tab.js
index e2cf085bb9c8442cd725cc881c9bbb156d01b0e6..e11acc33b6e241346e74e61da3498951ea7a1b5a 100644
--- a/chrome/browser/resources/ntp4/new_tab.js
+++ b/chrome/browser/resources/ntp4/new_tab.js
@@ -113,6 +113,17 @@ cr.define('ntp4', function() {
                               false);
     chrome.send('getMostVisited');
 
+    if (templateData.isWebStoreExperimentEnabled) {
+      var webstoreLink = localStrings.getString('webStoreLink');
+      var url = appendParam(webstoreLink, 'utm_source', 'chrome-ntp-launcher');
+      $('chrome-web-store-href').href = url;
+
+      $('chrome-web-store-href').addEventListener('click',
+          onChromeWebStoreButtonClick);
+
+      $('footer-content').classList.add('enable-cws-experiment');
+    }
+
     if (localStrings.getString('login_status_message')) {
       loginBubble = new cr.ui.Bubble;
       loginBubble.anchorNode = $('login-container');
@@ -173,6 +184,17 @@ cr.define('ntp4', function() {
   }
 
   /**
+   * Launches the chrome web store app with the chrome-ntp-launcher
+   * source.
+   * @param {Event} e The click event.
+   */
+  function onChromeWebStoreButtonClick(e) {
+    chrome.send('recordAppLaunchByURL',
+                [encodeURIComponent(this.href),
+                 ntp4.APP_LAUNCH.NTP_WEBSTORE_FOOTER]);
+  }
+
+  /**
    * Fills in an invisible div with the 'Most Visited' string so that
    * its length may be measured and the nav dots sized accordingly.
    */