Fix closure issues

Author: kevinpschaaf

externs/polymer-externs.js

@@ -147,6 +147,9 @@ Polymer.legacyWarnings;
 /** @type {boolean} */
 Polymer.legacyNotifyOrder;
 
+/** @type {boolean} */
+Polymer.orderedComputed;
+
 // nb. This is explicitly 'var', as Closure Compiler checks that this is the case.
 /**
  * @constructor

lib/mixins/property-effects.js

@@ -553,9 +553,10 @@ function propertyIsDirty(inst, trigger, changedProps, hasPaths) {
         }
       }
     });
+    return false;
   } else {
-    return changedProps && trigger.rootProperty in changedProps ||
-          inst.__dataPending && trigger.rootProperty in inst.__dataPending;
+    return Boolean(changedProps && trigger.rootProperty in changedProps ||
+      inst.__dataPending && trigger.rootProperty in inst.__dataPending);
   }
 }