Add links to MP and resolve minor fixes

appengine/swarming/elements/res/imp/tasklist/task-list.html

Index: appengine/swarming/elements/res/imp/tasklist/task-list.html
diff --git a/appengine/swarming/elements/res/imp/tasklist/task-list.html b/appengine/swarming/elements/res/imp/tasklist/task-list.html
index d0be40c41e89ff8ab7f069f5a8c4c6faddfd3aa0..f0d4b185b0a3fd0df554c6b65f249affc307e884 100644
--- a/appengine/swarming/elements/res/imp/tasklist/task-list.html
+++ b/appengine/swarming/elements/res/imp/tasklist/task-list.html
@@ -248,7 +248,7 @@
   </template>
   <script>
   (function(){
-    var specialColumns = ["deduped_from", "name", "state", "bot"];
+    var specialColumns = ["deduped_from", "name", "state", "bot", "sk_revision"];

[M-A Ruel, 2016/10/12 19:35:07]

This is still very one off. I would have preferred something even more generic.
I understand that this means going back and changing the tag associated to the
tasks. So my take is to:
- Decide for a generic tag name to designate the root commit URL and the commit
hash.
- In addition to this one, add the other one with a more generic name.
- Migrate task triggering to use the new tag.
- Remove sk_ specific code in there.

Same for sk_repo below.

While the above can be done in a follow up, please update
https://github.com/luci/luci-py/blob/master/appengine/swarming/doc/Magic-Valu...
in this CL with information about the special parsing of this tag.

[kjlubick, 2016/10/12 20:02:38]

I can take care of it in this CL and update our swarming task scheduler later. 
Magic Values have been added as source_revision and source_repo.

 
     // Given a time attribute like "abandoned_ts", humanTime returns a function
     // that returns the human-friendly version of that attribute. The human
@@ -424,10 +424,11 @@
 
       _skLink: function(task) {
         var r = this._attribute(task, "sk_revision")[0];
-        if (r === "none") {
+        var repo = this._attribute(task, "sk_repo")[0];
+        if (r === "none" || repo === "none") {
           return false;
         }
-        return "https://skia.googlesource.com/skia/+/" + r;
+        return repo + "/+/"+ r;

[M-A Ruel, 2016/10/12 19:35:07]

This is completely GoB specific. I'd like something that would work with
arbitrary git hosting service, e.g. github.

[kjlubick, 2016/10/12 20:02:38]

Done.  Like the other things, it's a "replace %s with the thing you want"

       },
 
       _tag: function(task, col) {