move top-level internal methods into a class

tools/dom/templates/html/impl/impl_Element.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;
 
 class _ChildrenElementList extends ListBase<Element> {
   // Raw Element.
   final Element _element;
   final HtmlCollection _childElements;
@@ skipping 672 matching lines @@
       self._attributeBindings = new Map<String, StreamSubscription>();
     }
 
     self.xtag.attributes.remove(name);
 
     var changed;
     if (name.endsWith('?')) {
       name = name.substring(0, name.length - 1);
 
       changed = (value) {
-        if (_templateBooleanConversion(value)) {
+        if (_Bindings._toBoolean(value)) {
           self.xtag.attributes[name] = '';
         } else {
           self.xtag.attributes.remove(name);
         }
       };
     } else {
       changed = (value) {
         // TODO(jmesserly): escape value if needed to protect against XSS.
         // See https://github.com/toolkitchen/mdv/issues/58
         self.xtag.attributes[name] = value == null ? '' : '$value';
@@ skipping 112 matching lines @@
    * Creates an instance of the template.
    * This is only supported if [isTemplate] is true.
    */
   @Experimental
   DocumentFragment createInstance() {
     _ensureTemplate();
 
     var template = ref;
     if (template == null) template = this;
 
-    var instance = _createDeepCloneAndDecorateTemplates(template.content,
-        attributes['syntax']);
+    var instance = _Bindings._createDeepCloneAndDecorateTemplates(
+        template.content, attributes['syntax']);
 
     if (TemplateElement._instanceCreated != null) {
       TemplateElement._instanceCreated.add(instance);
     }
     return instance;
   }
 
   /**
    * The data model which is inherited through the tree.
    * This is only supported if [isTemplate] is true.
    *
    * Setting this will destructive propagate the value to all descendant nodes,
    * and reinstantiate all of the nodes expanded by this template.
    *
    * Currently this does not support propagation through Shadow DOMs.
    */
   @Experimental
   get model => _model;
 
   @Experimental
   void set model(value) {
     _ensureTemplate();
 
     var syntax = TemplateElement.syntax[attributes['syntax']];
     _model = value;
-    _addBindings(this, model, syntax);
+    _Bindings._addBindings(this, model, syntax);
   }
 
   // TODO(jmesserly): const set would be better
   static const _TABLE_TAGS = const {
     'caption': null,
     'col': null,
     'colgroup': null,
     'tbody': null,
     'td': null,
     'tfoot': null,
@@ skipping 168 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }