Reorganize mdv and observe packages

tools/dom/templates/html/impl/impl_Node.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of $LIBRARYNAME;
 
 /**
  * Lazy implementation of the child nodes of an element that does not request
  * the actual child nodes of an element until strictly necessary greatly
  * improving performance for the typical cases where it is not required.
@@ skipping 161 matching lines @@
   int get length => _this.$dom_childNodes.length;
 
   void set length(int value) {
     throw new UnsupportedError(
         "Cannot set length on immutable List.");
   }
 
   Node operator[](int index) => _this.$dom_childNodes[index];
 }
 
+/**
+ * The MDV package, if available.
+ *
+ * This can be used to initialize MDV support via:
+ *
+ *     import 'dart:html';
+ *     import 'package:mdv/mdv.dart' as mdv;
+ *     main() {
+ *       mdv.initialize();
+ *     }
+ */
+Function mdvPackage = (node) {
+  throw new UnsupportedError("The MDV package is not available. "
+      "You can enable it with `import 'package:mdv/mdv.dart' as mdv;` and "
+      "`mdv.initialize()`");
+};
+
+/** Information about the instantiated template. */
+class TemplateInstance {
+  // TODO(rafaelw): firstNode & lastNode should be read-synchronous
+  // in cases where script has modified the template instance boundary.
+
+  /** The first node of this template instantiation. */
+  final Node firstNode;
+
+  /**
+   * The last node of this template instantiation.
+   * This could be identical to [firstNode] if the template only expanded to a
+   * single node.
+   */
+  final Node lastNode;
+
+  /** The model used to instantiate the template. */
+  final model;
+
+  TemplateInstance(this.firstNode, this.lastNode, this.model);
+}
+
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   List<Node> get nodes {
     return new _ChildNodeListLazy(this);
   }
 
   void set nodes(Iterable<Node> value) {
     // Copy list first since we don't want liveness during iteration.
     // TODO(jacobr): there is a better way to do this.
     List copy = new List.from(value);
     text = '';
@@ skipping 59 matching lines @@
    * Print out a String representation of this Node.
    */
   String toString() => nodeValue == null ? super.toString() : nodeValue;
 
   /**
    * Binds the attribute [name] to the [path] of the [model].
    * Path is a String of accessors such as `foo.bar.baz`.
    */
   @Experimental
   void bind(String name, model, String path) {
-    // TODO(jmesserly): should we throw instead?
-    window.console.error('Unhandled binding to Node: '
-        '$this $name $model $path');
+    mdvPackage(this).bind(name, model, path);
   }
 
   /** Unbinds the attribute [name]. */
   @Experimental
-  void unbind(String name) {}
+  void unbind(String name) {
+    mdvPackage(this).unbind(name);
+  }
 
   /** Unbinds all bound attributes. */
   @Experimental
-  void unbindAll() {}
-
-  TemplateInstance _templateInstance;
+  void unbindAll() {
+    mdvPackage(this).unbindAll();
+  }
 
   /** Gets the template instance that instantiated this node, if any. */
   @Experimental
-  TemplateInstance get templateInstance =>
-      _templateInstance != null ? _templateInstance :
-      (parent != null ? parent.templateInstance : null);
+  TemplateInstance get templateInstance => mdvPackage(this).templateInstance;
 
 $!MEMBERS
 }