feat(scope): add new createProtoChild method

Internalizes PrototypeMap, and allows for easier switch to ContextLocals.

Author: rkirov

lib/core/scope.dart

@@ -379,6 +379,11 @@ class Scope {
     return child;
   }
 
+  /// Creates a child [Scope] that is prototypal with respect to current scope.
+  Scope createProtoChild() {
+    return createChild(new PrototypeMap(context));
+  }
+
   /**
    * Removes the current scope (and all of its children) from the parent scope. Removal implies
    * that calls to [digest] will no longer propagate to the current scope nor its children.

lib/core_dom/view.dart

@@ -55,7 +55,7 @@ class ViewPort {
   }
 
   View insertNew(ViewFactory viewFactory, { View insertAfter, Scope viewScope}) {
-    if (viewScope == null) viewScope = scope.createChild(new PrototypeMap(scope.context));
+    if (viewScope == null) viewScope = scope.createProtoChild();
     View view = viewFactory.call(viewScope, directiveInjector);
     return insert(view, insertAfter: insertAfter);
   }

lib/directive/ng_include.dart

@@ -45,7 +45,7 @@ class NgInclude {
 
   _updateContent(ViewFactory viewFactory) {
     // create a new scope
-    _scope = scope.createChild(new PrototypeMap(scope.context));
+    _scope = scope.createProtoChild();
     _view = viewFactory(_scope, directiveInjector);
 
     _view.nodes.forEach((node) => element.append(node));

lib/directive/ng_repeat.dart

@@ -172,9 +172,9 @@ class NgRepeat {
 
     addFn((CollectionChangeItem addition) {
       changeFunctions[addition.currentIndex] = (index, previousView) {
-        var childContext = _updateContext(new PrototypeMap(_scope.context), index,length)
+        var childScope = _scope.createProtoChild();
+        var childContext = _updateContext(childScope.context, index, length)
             ..[_valueIdentifier] = addition.item;
-        var childScope = _scope.createChild(childContext);
         var view = views[index] = _boundViewFactory(childScope);
         _viewPort.insert(view, insertAfter: previousView);
       };
@@ -222,7 +222,7 @@ class NgRepeat {
     _views = views;
   }
 
-  PrototypeMap _updateContext(PrototypeMap context, int index, int length) {
+  Map _updateContext(Map context, int index, int length) {
     var first = (index == 0);
     var last = (index == length - 1);
     return context

lib/directive/ng_switch.dart

@@ -81,7 +81,7 @@ class NgSwitch {
     val = '!$val';
     (cases.containsKey(val) ? cases[val] : cases['?'])
         .forEach((_Case caze) {
-          Scope childScope = scope.createChild(new PrototypeMap(scope.context));
+          Scope childScope = scope.createProtoChild();
           var view = caze.viewFactory(childScope);
           caze.anchor.insert(view);
           currentViews.add(new _ViewScopePair(view, caze.anchor,

lib/routing/ng_view.dart

@@ -120,7 +120,7 @@ class NgView implements DetachAware, RouteProvider {
         _viewCache.fromUrl(viewDef.template, newDirectives, Uri.base);
     viewFuture.then((ViewFactory viewFactory) {
       _cleanUp();
-      _childScope = _scope.createChild(new PrototypeMap(_scope.context));
+      _childScope = _scope.createProtoChild();
       _view = viewFactory(_childScope, _dirInjector);
       _view.nodes.forEach((elm) => _element.append(elm));
     });

test/core/scope_spec.dart

@@ -238,9 +238,9 @@ void main() {
         });
 
         it('children should point to root', (RootScope rootScope) {
-          var child = rootScope.createChild(new PrototypeMap(rootScope.context));
+          var child = rootScope.createProtoChild();
           expect(child.rootScope).toEqual(rootScope);
-          expect(child.createChild(new PrototypeMap(rootScope.context)).rootScope).toEqual(rootScope);
+          expect(child.createProtoChild().rootScope).toEqual(rootScope);
         });
       });
 
@@ -253,11 +253,11 @@ void main() {
 
 
         it('should point to parent', (RootScope rootScope) {
-          var child = rootScope.createChild(new PrototypeMap(rootScope.context));
+          var child = rootScope.createProtoChild();
           expect(child.id).toEqual(':0');
           expect(rootScope.parentScope).toEqual(null);
           expect(child.parentScope).toEqual(rootScope);
-          expect(child.createChild(new PrototypeMap(rootScope.context)).parentScope).toEqual(child);
+          expect(child.createProtoChild().parentScope).toEqual(child);
         });
       });
     });
@@ -274,7 +274,7 @@ void main() {
 
         it(r'should add listener for both emit and broadcast events', (RootScope rootScope) {
           var log = '',
-          child = rootScope.createChild(new PrototypeMap(rootScope.context));
+          child = rootScope.createProtoChild();
 
           eventFn(event) {
             expect(event).not.toEqual(null);
@@ -294,7 +294,7 @@ void main() {
 
         it(r'should return a function that deregisters the listener', (RootScope rootScope) {
           var log = '';
-          var child = rootScope.createChild(new PrototypeMap(rootScope.context));
+          var child = rootScope.createProtoChild();
           var subscription;
 
           eventFn(e) {

test/directive/ng_repeat_spec.dart

@@ -529,7 +529,7 @@ main() {
     it('should correctly handle detached state', () {
       scope.context['items'] = [1];
 
-      var parentScope = scope.createChild(new PrototypeMap(scope.context));
+      var parentScope = scope.createProtoChild();
       element = compile(
         '<ul>'
           '<li ng-repeat="item in items">{{item}}</li>'