Add support for isInert to allow elements to boot up in an inert st…

…ate. e.g. `<x-foo is-inert></x-foo>`. Setting `xFoo.isInert = false` causes the element to boot up.

polymer.html

@@ -65,7 +65,7 @@
       // setup gestures
       this._setupGestures();
       // manage configuration
-      this._setupConfigure();
+      this._setupConfigure(this.__data__);
       // setup style properties
       this._setupStyleProperties();
       // setup debouncers

src/lib/base.html

@@ -64,6 +64,17 @@
     },
 
     createdCallback: function() {
+      if (Polymer.Settings.enableInert && this.hasAttribute('is-inert')) {
+        this.__data__ = {
+          isInert: true
+        };
+        this._propertySetter = inertPropertySetter;
+      } else {
+        this.__initialize();
+      }
+    },
+
+    __initialize: function() {
       if (!this.__hasRegisterFinished) {
         this._ensureRegisterFinished(this.__proto__);
       }
@@ -288,6 +299,32 @@
   Polymer.Base = Polymer.Base.chainObject(Polymer.Base, HTMLElement.prototype);
   Polymer.BaseDescriptors = {};
 
+  if (Polymer.Settings.enableInert) {
+
+    var inertPropertySetter = function(property, value) {
+      this.__data__[property] = value;
+    }
+
+    var inertDesc = {
+      configurable: true,
+      writeable: true,
+      set: function(val) {
+        if (!val && this.isInert) {
+          this.__data__.isInert = false;
+          this._propertySetter = Polymer.Bind._modelApi._propertySetter;
+          this.__initialize();
+          this.removeAttribute('is-inert');
+        }
+      },
+      get: function() {
+        return this.__data__.isInert;
+      }
+    }
+
+    Polymer.BaseDescriptors.isInert = inertDesc;
+    Object.defineProperty(Polymer.Base, 'isInert', inertDesc);
+  }
+
   if (window.CustomElements) {
     Polymer.instanceof = CustomElements.instanceof;
   } else {

src/lib/polymer-bootstrap.html

@@ -70,6 +70,9 @@
     }
 
     Polymer.Class = function(prototype) {
+      if (!prototype.factoryImpl) {
+        prototype.factoryImpl = function() {}
+      }
       return desugar(prototype).constructor;
     }