Make tasklist and taskpage use subsecond durations

appengine/swarming/ui/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
@@ skipping 139 matching lines @@
             console.log("ignoring failure because a second request happened.");
             this.splice(busyArr, idx, 1, {status:false});
             return;
           }
           this.splice(busyArr, idx, 1, {status:false});
           return Promise.reject(reason);
         }.bind(this));
       },
 
       _humanDuration: function(timeInSecs) {
-        return sk.human.strDuration(timeInSecs) || "0s";
+        // If the timeInSecs is 0 (e.g. duration of Terminate bot tasks), we
+        // still want to display 0s.
+        if (timeInSecs === 0 || timeInSecs === "0") {

[stephana, 2017/05/31 15:00:42]

.... timeInSecs === "0" should be omitted IMO. String values can be handled by
the subsequent clauses. If it is '' it will be falsey and otherwise parseFloat
will take care of it. 

[kjlubick, 2017/05/31 15:02:53]

I put it in there such that 0 and "0" become "0s" Otherwise, the later becomes
"0.00s" and the inconsistency looks strange. 

[stephana, 2017/05/31 17:29:19]

Ack

+          return "0s";
+        }
+        // Otherwise, if timeInSecs is falsey (e.g. undefined), return empty
+        // string to reflect that.
+        if (!timeInSecs) {
+          return "";
+        }
+        ptimeInSecs = parseFloat(timeInSecs);
+        // On a bad parse (shouldn't happen), show original.
+        if (!ptimeInSecs) {
+          return timeInSecs + " seconds";
+        }
+
+        // For times greater than a minute, make them human readable
+        // e.g. 2h 43m or 13m 42s
+        if (ptimeInSecs > 60){
+          return sk.human.strDuration(ptimeInSecs);
+        }
+        // For times less than a minute, add 10ms resolution.
+        return ptimeInSecs.toFixed(2)+"s";
       },
 
       _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++) {
@@ skipping 68 matching lines @@
         }
         return this._humanDuration((second.getTime() - first.getTime())/1000);
       },
 
       _truthy: function(a){
         return !!a;
       }
     };
   })();
 </script>