Update waterfall templates to include Milo link.

masters/master.chromium/public_html/milo.js

+// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function MiloInject(root, mastername) {
+  // Get our ".header" <div> (in "layout.html").
+  var header = document.querySelector(".header");
+  if (! header) {
+    return;
+  }
+
+  // Do we have a Milo substitution avialable?

[estaab, 2016/11/09 23:24:56]

available

[dnj, 2016/11/10 00:22:55]

Done.

+  var path = window.location.pathname;
+  var desc = null;
+  var miloPath = path;
+  [
+    {
+      re: /^(?:\/[ip]\/([^\/]+))?\/builders\/([^\/]+)$/,
+      desc: "builder faster",
+      replacer: function(match, master, builder, offset, string) {
+        master = mastername || master;
+        if (! master) {
+          return string;
+        }
+        return ["buildbot", master, builder].join("/");
+      },
+    },
+    {
+      re: /^(?:\/[ip]\/([^\/]+))?\/builders\/([^\/]+)\/builds\/([^\/]+)\/$/,
+      desc: "build faster and forever",
+      replacer: function(match, master, builder, buildno, offset, string) {
+        master = mastername || master;
+        if (! master) {
+          return string;
+        }
+        return ["buildbot", master, builder, buildno].join("/");
+      },
+    },
+  ].every(function(e) {
+    miloPath = path.replace(e.re, e.replacer);
+    desc = e.desc;
+    return (miloPath === path);
+  });
+  if (miloPath === path) {
+    return;
+  }
+
+  // Build our milo elements.
+  miloPath = "https://luci-milo.appspot.com/" + miloPath;
+  var miloElement = document.createElement("span");
+  miloElement.className = "header-right-align";
+  miloElement.innerHTML += `

[estaab, 2016/11/09 23:24:56]

Not sure if we're supposed to be using ES6 templates but I guess we can find out
if anyone is using an old browser and complains. :)

[dnj, 2016/11/10 00:22:55]

SGTM. It's been in Chromium since M41, and we're on M53 right now, so I'm
completely okay with this :)

[estaab, 2016/11/10 00:29:27]

Someone on the web platform team pushed back when I did it so I thought I'd
follow their lead and do a nudge. No real objections of my own. :)

+    <div class="milo-container">
+      <a class="milo-link" href="${miloPath}">
+        <img class=".milo-logo"
+            src="${root}chrome-infra-logo-32x32.png" />[LogDog]</a>
+      <div class="milo-info">
+        <div>View this ${desc} with LogDog / Milo!</div>
+        <p></p>
+        <div><a href="${miloPath}">Permalink</a></div>
+        <p></p>
+        <div class="milo-cit-info">
+          <img src="${root}chrome-infra-logo-32x32.png"></img>
+          <span>Part of Chrome Infrastructure Team's LUCI project.</span>
+        </div>
+      </div>
+    </div>
+  `;
+  header.appendChild(miloElement);
+}