Refactor out reusable pieces from new Botlist

appengine/swarming/elements/res/imp/common/swarming-app.html

Index: appengine/swarming/elements/res/imp/common/swarming-app.html
diff --git a/appengine/swarming/elements/res/imp/common/swarming-app.html b/appengine/swarming/elements/res/imp/common/swarming-app.html
index 27031dcb305d13a65aeda1ed2d19205ba603313e..325c8b8dc16600301d995b3e4fa34d3b1de5a580 100644
--- a/appengine/swarming/elements/res/imp/common/swarming-app.html
+++ b/appengine/swarming/elements/res/imp/common/swarming-app.html
@@ -18,6 +18,17 @@
   <style include="shared-style"> contains styles to be shared among all
       apps, such as colors.
 
+  It contains the definition of the following Behaviors:
+
+    SwarmingBehaviors.SwarmingBehavior
+
+  To use it, include
+      behaviors: [SwarmingBehaviors.SwarmingBehavior]
+  in the creation of any Polymer element.
+
+  SwarmingBehaviors.SwarmingBehavior contains shared functions to ease
+  templating, such as _or() and _not().
+
   Properties:
     auth_headers: Object, Use this in iron-ajax to set oauth2 headers.
     busy: Boolean, If the busy spinner should be active.
@@ -135,4 +146,26 @@
         color: #1F78B4;
       }
   </style>
-</dom-module>
+</dom-module>
+
+<script>
+  window.SwarmingBehaviors = window.SwarmingBehaviors || {};
+  (function(){
+    // This behavior wraps up all the shared swarming functionality.
+    SwarmingBehaviors.SwarmingBehavior = {
+
+      _not: function(a) {
+        return !a;
+      },
+
+      _or: function() {
+        var result = false;
+        // can't use .foreach, as arguments isn't really an Array.
+        for (var i = 0; i < arguments.length; i++) {
+          result = result || arguments[i];
+        }
+        return result;
+      },
+    };
+  })();
+</script>