Template anchor comments are now cloned rather than created.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=149701321

Author: leonsenft

lib/src/compiler/identifiers.dart

@@ -81,8 +81,9 @@ var impEMPTY_MAP = EMPTY_MAP;
 
 class Identifiers {
   static final appViewUtils = new CompileIdentifierMetadata(
-      name: "appViewUtils",
-      moduleUrl: 'asset:angular2/lib/src/core/linker/app_view_utils.dart');
+      name: "appViewUtils", moduleUrl: APP_VIEW_UTILS_MODULE_URL);
+  static final ngAnchor = new CompileIdentifierMetadata(
+      name: 'ngAnchor', moduleUrl: APP_VIEW_MODULE_URL);
   static final AppView = new CompileIdentifierMetadata(
       name: "AppView", moduleUrl: APP_VIEW_MODULE_URL);
   static final DebugAppView = new CompileIdentifierMetadata(

lib/src/compiler/output/output_interpreter.dart

@@ -670,6 +670,7 @@ var CATCH_STACK_VAR = "stack";
 /// them dynamically.
 void _initializeInterpreter() {
   Identifiers.DebugAppView.runtime = DebugAppView;
+  Identifiers.ngAnchor.runtime = ngAnchor;
   Identifiers.AppView.runtime = AppView;
   Identifiers.ViewContainer.runtime = ViewContainer;
   Identifiers.StaticNodeDebugInfo.runtime = StaticNodeDebugInfo;

lib/src/compiler/view_compiler/view_builder.dart

@@ -48,12 +48,13 @@ import "view_compiler_utils.dart"
         createFlatArray,
         createDiTokenExpression,
         createSetAttributeParams,
-        componentFromDirectives,
-        TEMPLATE_COMMENT_TEXT;
+        componentFromDirectives;
 
 const IMPLICIT_TEMPLATE_VAR = "\$implicit";
 const CLASS_ATTR = "class";
 const STYLE_ATTR = "style";
+var cloneAnchorNodeExpr =
+    o.importExpr(Identifiers.ngAnchor).callMethod('clone', [o.literal(false)]);
 var parentRenderNodeVar = o.variable("parentRenderNode");
 var rootSelectorVar = o.variable("rootSelector");
 var NOT_THROW_ON_CHANGES = o.not(o.importExpr(Identifiers.throwOnChanges));
@@ -432,25 +433,20 @@ class ViewBuilderVisitor implements TemplateAstVisitor {
     var nodeIndex = this.view.nodes.length;
     var fieldName = '_anchor_${nodeIndex}';
     o.Expression anchorVarExpr;
-    // Create a comment to serve as anchor for template.
+    // Clone template anchor.
     if (createFieldForAnchor) {
       view.fields.add(new o.ClassField(fieldName,
           outputType: o.importType(Identifiers.HTML_COMMENT_NODE),
           modifiers: const [o.StmtModifier.Private]));
       anchorVarExpr = new o.ReadClassMemberExpr(fieldName);
-      var createAnchorNodeExpr = new o.WriteClassMemberExpr(
-          fieldName,
-          o
-              .importExpr(Identifiers.HTML_COMMENT_NODE)
-              .instantiate([o.literal(TEMPLATE_COMMENT_TEXT)]));
-      view.createMethod.addStmt(createAnchorNodeExpr.toStmt());
+      var assignCloneAnchorNodeExpr =
+          new o.WriteClassMemberExpr(fieldName, cloneAnchorNodeExpr);
+      view.createMethod.addStmt(assignCloneAnchorNodeExpr.toStmt());
     } else {
-      var readVarExp = o.variable(fieldName);
-      anchorVarExpr = readVarExp;
-      var createAnchorNodeExpr = readVarExp.set(o
-          .importExpr(Identifiers.HTML_COMMENT_NODE)
-          .instantiate([o.literal(TEMPLATE_COMMENT_TEXT)]));
-      view.createMethod.addStmt(createAnchorNodeExpr.toDeclStmt());
+      var readVarExpr = o.variable(fieldName);
+      anchorVarExpr = readVarExpr;
+      var assignCloneAnchorNodeExpr = readVarExpr.set(cloneAnchorNodeExpr);
+      view.createMethod.addStmt(assignCloneAnchorNodeExpr.toDeclStmt());
     }
     var addCommentStmt = _getParentRenderNode(parent)
         .callMethod('append', [anchorVarExpr], checked: true)

lib/src/compiler/view_compiler/view_compiler_utils.dart

@@ -10,9 +10,6 @@ import '../identifiers.dart' show Identifiers;
 import '../output/output_ast.dart' as o;
 import 'compile_view.dart' show CompileView;
 
-// Template Anchor comment.
-const TEMPLATE_COMMENT_TEXT = 'template bindings={}';
-
 // Creates method parameters list for AppView set attribute calls.
 List<o.Expression> createSetAttributeParams(
     String fieldName, String attrNs, String attrName, o.Expression valueExpr) {

lib/src/core/linker/app_view.dart

@@ -19,6 +19,9 @@ import 'view_type.dart' show ViewType;
 
 export 'package:angular2/src/core/change_detection/component_state.dart';
 
+/// Template anchor comment for cloning.
+var ngAnchor = new Comment('template bindings={}');
+
 const _UndefinedInjectorResult = const Object();
 const String appViewRootElementName = 'rootEl';
 bool domRootRendererIsDirty = false;

test/source_gen/template_compiler/test_files/core_directives.template_debug.golden

@@ -74,7 +74,7 @@ class ViewTestFooComponent0 extends DebugAppView<import5.TestFooComponent> {
     Text _text_0 = new Text('    ');
     parentRenderNode.append(_text_0);
     dbgElm(_text_0, 0, 0, 0);
-    var _anchor_1 = new Comment('template bindings={}');
+    var _anchor_1 = ngAnchor.clone(false);
     parentRenderNode?.append(_anchor_1);
     dbgElm(_anchor_1, 1, 0, 4);
     _appEl_1 = new ViewContainer(1, null, this, _anchor_1);
@@ -84,7 +84,7 @@ class ViewTestFooComponent0 extends DebugAppView<import5.TestFooComponent> {
     Text _text_2 = new Text('\n    ');
     parentRenderNode.append(_text_2);
     dbgElm(_text_2, 2, 0, 30);
-    var _anchor_3 = new Comment('template bindings={}');
+    var _anchor_3 = ngAnchor.clone(false);
     parentRenderNode?.append(_anchor_3);
     dbgElm(_anchor_3, 3, 1, 4);
     _appEl_3 = new ViewContainer(3, null, this, _anchor_3);

test/source_gen/template_compiler/test_files/core_directives.template_release.golden

@@ -55,15 +55,15 @@ class ViewTestFooComponent0 extends AppView<import1.TestFooComponent> {
     final HtmlElement parentRenderNode = initViewRoot(rootEl);
     Text _text_0 = new Text('    ');
     parentRenderNode.append(_text_0);
-    var _anchor_1 = new Comment('template bindings={}');
+    var _anchor_1 = ngAnchor.clone(false);
     parentRenderNode?.append(_anchor_1);
     _appEl_1 = new ViewContainer(1, null, this, _anchor_1);
     TemplateRef _TemplateRef_1_4 =
         new TemplateRef(_appEl_1, viewFactory_TestFooComponent1);
     _NgIf_1_5 = new NgIf(_appEl_1, _TemplateRef_1_4);
     Text _text_2 = new Text('\n    ');
     parentRenderNode.append(_text_2);
-    var _anchor_3 = new Comment('template bindings={}');
+    var _anchor_3 = ngAnchor.clone(false);
     parentRenderNode?.append(_anchor_3);
     _appEl_3 = new ViewContainer(3, null, this, _anchor_3);
     TemplateRef _TemplateRef_3_4 =

test/source_gen/template_compiler/test_files/view_annotation.template_debug.golden

@@ -64,7 +64,7 @@ class ViewTestFooComponent0 extends DebugAppView<import4.TestFooComponent> {
   }
   ComponentRef build() {
     final HtmlElement parentRenderNode = initViewRoot(rootEl);
-    var _anchor_0 = new Comment('template bindings={}');
+    var _anchor_0 = ngAnchor.clone(false);
     parentRenderNode?.append(_anchor_0);
     dbgElm(_anchor_0, 0, 0, 0);
     _appEl_0 = new ViewContainer(0, null, this, _anchor_0);

test/source_gen/template_compiler/test_files/view_annotation.template_release.golden

@@ -50,7 +50,7 @@ class ViewTestFooComponent0 extends AppView<import1.TestFooComponent> {
   }
   ComponentRef build() {
     final HtmlElement parentRenderNode = initViewRoot(rootEl);
-    var _anchor_0 = new Comment('template bindings={}');
+    var _anchor_0 = ngAnchor.clone(false);
     parentRenderNode?.append(_anchor_0);
     _appEl_0 = new ViewContainer(0, null, this, _anchor_0);
     TemplateRef _TemplateRef_0_4 =