Add new botlist for swarming

appengine/swarming/elements/build/js/common.js

Index: appengine/swarming/elements/build/js/common.js
diff --git a/appengine/swarming/elements/build/js/common.js b/appengine/swarming/elements/build/js/common.js
new file mode 100644
index 0000000000000000000000000000000000000000..0222686f2ceec2ad6e2b6d2fdc7c04ae1b7ff7a3
--- /dev/null
+++ b/appengine/swarming/elements/build/js/common.js
@@ -0,0 +1,53 @@
+// 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.
+
+window.swarming = window.swarming || function() {
+  var swarming = {};
+
+  swarming.stableSort = function(arr, comp) {
+    if (!arr || !comp) {
+      console.log("missing arguments to stableSort", arr, comp);
+      return;
+    }
+    // We can guarantee a potential non-stable sort (like V8's
+    // Array.prototype.sort()) to be stable by first storing the index in the
+    // original sorting and using that if the original compare was 0.
+    arr.forEach(function(e, i){
+      if (e !== undefined && e !== null) {
+        e.__sortIdx = i;
+      }
+    });
+
+    arr.sort(function(a, b){
+      // undefined and null elements always go last.
+      if (a === undefined || a === null) {
+        if (b === undefined || b === null) {
+          return 0;
+        }
+        return 1;
+      }
+      if (b === undefined || b === null) {
+        return -1;
+      }
+      var c = comp(a, b);
+      if (c === 0) {
+        return a.__sortIdx - b.__sortIdx;
+      }
+      return c;
+    });
+  }
+
+  // naturalCompare tries to use natural sorting (e.g. sort ints by value).
+  swarming.naturalCompare = function(a, b) {
+    // Try numeric, aka "natural" sort and use it if ns is not NaN.
+    // Javascript will try to corece these to numbers or return NaN.
+    var ns = a - b;
+    if (ns) {
+      return ns;
+    }
+    return a.localeCompare(b);
+  }
+
+  return swarming;
+}();