Add histogram for how tab closing time. Did some cleanup along the way.

chrome/browser/resources/new_new_tab.js

 
 // Helpers
 
 function $(id) {
   return document.getElementById(id);
 }
 
 // TODO(arv): Remove these when classList is available in HTML5.
 // https://bugs.webkit.org/show_bug.cgi?id=20709
 function hasClass(el, name) {
@@ skipping 1310 matching lines @@
 
 $('thumb-checkbox').addEventListener('change',
                                      getCheckboxHandler(Section.THUMB));
 $('thumb-checkbox').addEventListener('keydown',
                                      getCheckboxHandler(Section.THUMB));
 $('list-checkbox').addEventListener('change',
                                     getCheckboxHandler(Section.LIST));
 $('list-checkbox').addEventListener('keydown',
                                     getCheckboxHandler(Section.LIST));
 
-window.addEventListener('load', bind(logEvent, global, 'NewTab.Onload', true));
+window.addEventListener('load', bind(logEvent, global, 'Tab.NewTabOnload', true));
 window.addEventListener('load', onDataLoaded);
 
 window.addEventListener('resize', handleWindowResize);
 document.addEventListener('DOMContentLoaded',
-    bind(logEvent, global, 'NewTab.DOMContentLoaded', true));
+    bind(logEvent, global, 'Tab.NewTabDOMContentLoaded', true));
 
 // Whether or not we should send the initial 'GetSyncMessage' to the backend
 // depends on the value of the attribue 'syncispresent' which the backend sets
 // to indicate if there is code in the backend which is capable of processing
 // this message. This attribute is loaded by the JSTemplate and therefore we
 // must make sure we check the attribute after the DOM is loaded.
 document.addEventListener('DOMContentLoaded',
                           callGetSyncMessageIfSyncIsPresent);
 
 // This link allows user to make new tab page as homepage from the new tab
@@ skipping 335 matching lines @@
 function fixLinkUnderline(el) {
   var span = document.createElement('span');
   span.className = 'link-color';
   while (el.hasChildNodes()) {
     span.appendChild(el.firstChild);
   }
   el.appendChild(span);
 }
 
 updateAttribution();