dart2js: Use frequency of occurence to sort metadata indices.

pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart

 // Copyright (c) 2013, 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 dart2js.js_emitter;
 
 /// This class should morph into something that makes it easy to build
 /// JavaScript representations of libraries, class-sides, and instance-sides.
 /// Initially, it is just a placeholder for code that is moved from
 /// [CodeEmitterTask].
@@ skipping 112 matching lines @@
       tearOffInfo.add(new jsAst.LiteralString(callSelectorString));
     }
 
     expressions
         ..addAll(tearOffInfo)
         ..add((tearOffName == null || member.isAccessor)
               ? js("null") : js.string(tearOffName))
         ..add(js.number(requiredParameterCount))
         ..add(js.number(optionalParameterCount))
         ..add(memberTypeExpression == null ? js("null") : memberTypeExpression)
-        ..addAll(task.metadataCollector
-            .reifyDefaultArguments(member).map(js.number));
+        ..addAll(task.metadataCollector.reifyDefaultArguments(member));
 
     if (canBeReflected || canBeApplied) {
       parameters.forEachParameter((Element parameter) {
-        expressions.add(
-            js.number(task.metadataCollector.reifyName(parameter.name)));
+        expressions.add(task.metadataCollector.reifyName(parameter.name));
         if (backend.mustRetainMetadata) {
-          Iterable<int> metadataIndices =
+          Iterable<jsAst.Expression> metadataIndices =
               parameter.metadata.map((MetadataAnnotation annotation) {
             ConstantValue constant =
                 backend.constants.getConstantValueForMetadata(annotation);
             backend.constants.addCompileTimeConstantForEmission(constant);
             return task.metadataCollector.reifyMetadata(annotation);
           });
-          expressions.add(new jsAst.ArrayInitializer(
-              metadataIndices.map(js.number).toList()));
+          expressions.add(new jsAst.ArrayInitializer(metadataIndices.toList()));
         }
       });
     }
     if (canBeReflected) {
       jsAst.LiteralString reflectionName;
       if (member.isConstructor) {
         String reflectionNameString = emitter.getReflectionName(member, name);
         reflectionName =
             new jsAst.LiteralString(
                 '"new ${Elements.reconstructConstructorName(member)}"');
       } else {
         reflectionName =
             js.string(namer.privateName(member.memberName));
       }
       expressions
           ..add(reflectionName)
-          ..addAll(task.metadataCollector
-              .computeMetadata(member).map(js.number));
+          ..addAll(task.metadataCollector.computeMetadata(member));
     } else if (isClosure && canBeApplied) {
       expressions.add(js.string(namer.privateName(member.memberName)));
     }
 
     jsAst.ArrayInitializer arrayInit =
       new jsAst.ArrayInitializer(expressions.toList());
     compiler.dumpInfoTask.registerElementAst(member,
         builder.addProperty(name, arrayInit));
   }
 
   void addMemberField(Field field, ClassBuilder builder) {
     // For now, do nothing.
   }
 }