Milo: Add timestamp name and tooltip

milo/appengine/frontend/templates/pages/build.html

Index: milo/appengine/frontend/templates/pages/build.html
diff --git a/milo/appengine/frontend/templates/pages/build.html b/milo/appengine/frontend/templates/pages/build.html
index 39d1db164ac27dd85876285025b4fa5bed607ea7..bea3f39eddba2dda4a3895517f99ce8a60fdd751 100644
--- a/milo/appengine/frontend/templates/pages/build.html
+++ b/milo/appengine/frontend/templates/pages/build.html
@@ -153,7 +153,13 @@
               <div class="status-{{.Status}} result">
                 <b>Steps</b>
                 {{ if .Duration -}}
-                <span style="float:right">( {{ .Duration | humanDuration }} )</span>
+                <span style="float:right"

[nodir, 2017/04/29 01:26:40]

probably we will have more places where we need to express duration, so
repeating this code everywhere is not ideal. What about making a function or a
template that accepts duration, start time and end time and returns this span
with data-starttime date-endtime, etc

[hinoka, 2017/05/02 03:33:14]

the span might need other things though, like styles/classes to make it float to
the right.  I could make one for this specific span, but then it'd have to
contain the code to make it float to the right...  It might be premature
optimization, wdyt?

[nodir, 2017/05/02 14:58:02]

It might be premature generalization 

+                      class="duration"
+                      data-starttime="{{ .Started | formatTime }}"
+                      {{ if .Finished }}
+                        data-endtime="{{ .Finished | formatTime }}"
+                      {{ end }}>
+                      ( {{ .Duration | humanDuration }} )</span>
                 {{- end }}
               </div>
               <ul>
@@ -170,7 +176,13 @@
             <div class="status-{{.Status}} result">
               <b>{{.Label}}</b>
               {{ if .Duration -}}
-                <span style="float:right">( {{ .Duration | humanDuration }} )</span>
+              <span style="float:right"
+                    class="duration"
+                    data-starttime="{{ .Started | formatTime }}"
+                    {{ if .Finished }}
+                      data-endtime="{{ .Finished | formatTime }}"
+                    {{ end }}>
+                    ( {{ .Duration | humanDuration }} )</span>
               {{- end }}
               <span>
                 {{ range .Text -}}