dart2js: Use frequency of occurence to sort metadata indices.

pkg/js_ast/lib/src/template.dart

 // Copyright (c) 2014, 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 js_ast;
 
 class TemplateManager {
   Map<String, Template> expressionTemplates = new Map<String, Template>();
   Map<String, Template> statementTemplates = new Map<String, Template>();
 
@@ skipping 636 matching lines @@
           params.addAll(result);
         } else {
           params.add(result);
         }
       }
       Statement body = makeBody(arguments);
       return new Fun(params, body);
     };
   }
 
+  Instantiator visitDeferredExpression(DeferredExpression node) => same(node);
+
+  Instantiator visitDeferredNumber(DeferredNumber node) => same(node);
+
+  Instantiator visitDeferredString(DeferredString node) =>
+      (arguments) => node;
+
   Instantiator visitLiteralBool(LiteralBool node) =>
       (arguments) => new LiteralBool(node.value);
 
   Instantiator visitLiteralString(LiteralString node) =>
       (arguments) => new LiteralString(node.value);
 
   Instantiator visitLiteralNumber(LiteralNumber node) =>
       (arguments) => new LiteralNumber(node.value);
 
   Instantiator visitLiteralNull(LiteralNull node) =>
       (arguments) => new LiteralNull();
 
+  Instantiator visitStringConcatenation(StringConcatenation node) {
+    List<Instantiator> partMakers = node.parts
+        .map(visit)
+        .toList(growable: false);
+    return (arguments) {
+      List<Literal> parts = partMakers
+          .map((Instantiator instantiator) => instantiator(arguments))
+          .toList(growable: false);
+      return new StringConcatenation(parts);
+    };
+  }
+
   Instantiator visitArrayInitializer(ArrayInitializer node) {
     // TODO(sra): Implement splicing?
     List<Instantiator> elementMakers = node.elements
         .map(visit)
         .toList(growable: false);
     return (arguments) {
       List<Expression> elements = elementMakers
           .map((Instantiator instantiator) => instantiator(arguments))
           .toList(growable: false);
       return new ArrayInitializer(elements);
@@ skipping 67 matching lines @@
     if (count != before) containsInterpolatedNode.add(node);
     return null;
   }
 
   visitInterpolatedNode(InterpolatedNode node) {
     containsInterpolatedNode.add(node);
     if (node.isNamed) holeNames.add(node.nameOrPosition);
     ++count;
   }
 }