Add a timeline view to about:net-internals.

chrome/browser/resources/net_internals/time_util.js

Index: chrome/browser/resources/net_internals/time_util.js
===================================================================
--- chrome/browser/resources/net_internals/time_util.js	(revision 110334)
+++ chrome/browser/resources/net_internals/time_util.js	(working copy)
@@ -32,8 +32,18 @@
     return new Date(timeStampMs);
   }
 
+  /**
+   * Returns the current time.
+   *
+   * @returns {number} Milliseconds since the Unix epoch.
+   */
+  function getCurrentTime() {
+    return (new Date()).getTime();
+  }
+
   return {
     setTimeTickOffset: setTimeTickOffset,
-    convertTimeTicksToDate: convertTimeTicksToDate
+    convertTimeTicksToDate: convertTimeTicksToDate,
+    getCurrentTime: getCurrentTime
   };
 })();