add preventDispose property to prevent element unbinding when remove from document. Fixes #312

Author: sorvell

src/instance/base.js

@@ -67,7 +67,9 @@
       this.enteredViewCallback();
     },
     leftViewCallback: function() {
-      this.asyncUnbindAll();
+      if (!this.preventDispose) {
+        this.asyncUnbindAll();
+      }
       // invoke user action
       if (this.leftView) {
         this.leftView();

src/instance/mdv.js

@@ -52,8 +52,11 @@
         this.unbindAllProperties();
         this.super(); 
         // unbind shadowRoot
-        unbindNodeTree(this.shadowRoot);
-        // TODO(sjmiles): must also unbind inherited shadow roots
+        var root = this.shadowRoot;
+        while (root) {
+          unbindNodeTree(root);
+          root = root.olderShadowRoot;
+        }
         this._unbound = true;
       }
     },

test/html/unbind.html

@@ -72,12 +72,17 @@
         function(node) {
           chai.assert.isTrue(node.fooWasChanged, 'node is actually bound'); 
           var n = document.createElement('x-test');
-          n.cancelUnbindAll();
+          document.body.appendChild(n);
           return [n];
         },
+        function(node) {
+          node.preventDispose = true;
+          node.parentNode.removeChild(node);
+          return [node];
+        },
         function(node) {
           chai.assert.ok(!node._unbound, 
-            'element is bound when cancelUnbindAll is called');
+            'element is bound when preventDispose is true');
           node.unbindAll();
           chai.assert.isTrue(node._unbound, 
             'element is unbound when unbindAll is called');