Refactor prior to adding task-page

appengine/swarming/elements/res/imp/common/common-behavior.html

 <!--
   Copyright 2016 The LUCI Authors. All rights reserved.
   Use of this source code is governed under the Apache License, Version 2.0
   that can be found in the LICENSE file.
 
   It contains the definition of the following Behaviors:
 
     SwarmingBehaviors.CommonBehavior
 
   To use it, include
       behaviors: [SwarmingBehaviors.CommonBehavior]
   in the creation of any Polymer element.
 
   SwarmingBehaviors.CommonBehavior contains shared methods to ease
   templating, such as _or() and _not() as well as general utility methods
   such as _getJsonAsync.
  -->
 
 <script>
   window.SwarmingBehaviors = window.SwarmingBehaviors || {};
   (function(){
     // This behavior wraps up all the shared swarming functionality.
     SwarmingBehaviors.CommonBehavior = {
 
+      _botLink: function(bot_id) {
+        if (!bot_id) {
+          return undefined;
+        }
+        return "/newui/bot?id=" + bot_id;
+      },
+
       // _getJsonAsync makes an XHR to a url, parses the response as JSON
       // and sticks the resulting object into the property with the name given
       // by "bindTo". If busy is defined, the property with that name will be
       // set to true while the request is in flight and false afterwards.
       // request headers (e.g. authentication) and query params will be used if
       // provided. Query params is an object like {String:Array<String>}. On
       // error, bindTo will be set to false.  It is not set to undefined
       // because computed values in Polymer don't fire if a property is
       // undefined. Clients should check that bindTo is not falsey.
        _getJsonAsync: function(bindTo, url, busy, headers, params) {
@@ skipping 14 matching lines @@
           }
         }.bind(this)).catch(function(reason){
           console.log("Reason for failure of request to " + url, reason);
           this.set(bindTo, false);
           if (busy) {
             this.set(busy, false);
           }
         }.bind(this));
       },
 
+      _humanDuration: function(timeInSecs) {
+        return sk.human.strDuration(timeInSecs) || "0s";
+      },
+
       _not: function(a) {
         return !a;
       },
 
       _or: function() {
         var result = false;
         // can't use .foreach, as arguments isn't really an Array.
         for (var i = 0; i < arguments.length; i++) {
           result = result || arguments[i];
         }
         return result;
       },
+
+      _taskLink: function(task_id) {
+        if (!task_id) {
+          return undefined;
+        }
+        return "/newui/task?id=" + task_id;
+      },
+
+      // )timeDiffApprox returns the approximate difference between now and
+      // the specified date.
+      _timeDiffApprox: function(date){
+        if (!date) {
+          return "eons";
+        }
+        return sk.human.diffDate(date.getTime());
+      },
+
+      // timeDiffExact returns the exact difference between the two specified
+      // dates.  E.g. 2d 22h 22m 28s ago If a second date is not provided,
+      // now is used.
+      _timeDiffExact: function(first, second){
+        if (!first) {
+          return "eons";
+        }
+        if (!second) {
+          second = new Date();
+        }
+        return this._humanDuration((second.getTime() - first.getTime())/1000);
+      },
     };
   })();
 </script>