Swarming UI: Fix issue with negative pending time.

appengine/swarming/ui/res/imp/taskpage/task-page.html

Index: appengine/swarming/ui/res/imp/taskpage/task-page.html
diff --git a/appengine/swarming/ui/res/imp/taskpage/task-page.html b/appengine/swarming/ui/res/imp/taskpage/task-page.html
index ce78cbb592acc4618d15e8105d90a1d9cf23d8a2..a75fba0c55e4bbae79ce2976b0270fbd3e2ba17a 100644
--- a/appengine/swarming/ui/res/imp/taskpage/task-page.html
+++ b/appengine/swarming/ui/res/imp/taskpage/task-page.html
@@ -920,6 +920,9 @@
       },
 
       _duration: function(start, end) {
+        if (start.getTime() >= end.getTime()) {

[Ryan Tseng, 2017/06/07 22:06:59]

to avoid calling getTime() this many times, i'd probably do

var dur = end.getTime() - start.getTime()
if (dur < 0) dur = 0;
return dur;

[ayanaadylova, 2017/06/07 22:12:25]

Done.

+          return 0;
+        }
         return end.getTime() - start.getTime();
       },