Avoid emitting addStubs and tearOffCode when not needed.

pkg/compiler/lib/src/js_emitter/old_emitter/reflection_data_parser.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;
 
 // TODO(ahe): Share these with js_helper.dart.
 const FUNCTION_INDEX = 0;
 const NAME_INDEX = 1;
 const CALL_NAME_INDEX = 2;
@@ skipping 122 matching lines @@
       processedClasses.constructorsList.push(cls);
     }
     processedClasses.collected[cls] = [globalObject, newDesc];
     classes.push(cls);
   }
 }''', {'embeddedStatics': staticsAccess,
        'hasRetainedMetadata': backend.hasRetainedMetadata,
        'metadata': metadataAccess,
        'notInCspMode': !compiler.useContentSecurityPolicy});
 
+  // TODO(zarah): Remove empty else branches in output when if(#hole) is false.
   jsAst.Statement processStatics = js.statement('''
     function processStatics(descriptor, processedClasses) {
       for (var property in descriptor) {
         if (!hasOwnProperty.call(descriptor, property)) continue;
         if (property === "${namer.classDescriptorProperty}") continue;
         var element = descriptor[property];
         var firstChar = property.substring(0, 1);
         var previousProperty;
         if (firstChar === "+") {
           mangledGlobalNames[previousProperty] = property.substring(1);
@@ skipping 10 matching lines @@
           var optionalMethods = descriptor.$methodsWithOptionalArgumentsField;
           if (!optionalMethods) {
             descriptor.$methodsWithOptionalArgumentsField = optionalMethods = {}
           }
           optionalMethods[property] = previousProperty;
         } else if (typeof element === "function") {
           globalObject[previousProperty = property] = element;
           functions.push(property);
           #globalFunctions[property] = element;
         } else if (element.constructor === Array) {
-          addStubs(globalObject, element, property,
-                   true, descriptor, functions);
+          if (#needsArrayInitializerSupport) {
+            addStubs(globalObject, element, property,
+                     true, descriptor, functions);
+          }
         } else {
           // We will not enter this case if no classes are defined.
           if (#hasClasses) {
             previousProperty = property;
             processClassData(property, element, processedClasses);
           }
         }
       }
     }
 ''', {'typeInformation': typeInformationAccess,
       'globalFunctions': globalFunctionsAccess,
-      'hasClasses': oldEmitter.needsClassSupport});
+      'hasClasses': oldEmitter.needsClassSupport,
+      'needsArrayInitializerSupport': oldEmitter.needsArrayInitializerSupport});
 
 
   /**
    * See [dart2js.js_emitter.ContainerBuilder.addMemberMethod] for format of
    * [array].
    */
   jsAst.Statement addStubs = js.statement('''
   function addStubs(descriptor, array, name, isStatic,
                     originalDescriptor, functions) {
     var index = $FUNCTION_INDEX, alias = array[index], f;
@@ skipping 225 matching lines @@
 (function (reflectionData) {
   "use strict";
   #header;
   if (#needsClassSupport) {
     #defineClass;
     #inheritFrom;
     #finishClasses;
     #processClassData;
   }
   #processStatics;
-  #addStubs;
-  #tearOffCode;
+  if (#needsArrayInitializerSupport) {
+    #addStubs;
+    #tearOffCode;
+  }
   #incrementalSupport;
   #init;
 })''', {
       'header': header,
       'defineClass': oldEmitter.defineClassFunction,
       'inheritFrom': oldEmitter.buildInheritFrom(),
       'processClassData': processClassData,
       'processStatics': processStatics,
       'incrementalSupport': incrementalSupport,
       'addStubs': addStubs,
       'tearOffCode': tearOffCode,
       'init': init,
       'finishClasses': finishClasses,
-      'needsClassSupport': oldEmitter.needsClassSupport});
+      'needsClassSupport': oldEmitter.needsClassSupport,
+      'needsArrayInitializerSupport': oldEmitter.needsArrayInitializerSupport});
 }
 
 
 List<jsAst.Statement> buildTearOffCode(JavaScriptBackend backend) {
   Namer namer = backend.namer;
   Compiler compiler = backend.compiler;
 
   Element closureFromTearOff = backend.findHelper('closureFromTearOff');
   String tearOffAccessText;
   jsAst.Expression tearOffAccessExpression;
@@ skipping 101 matching lines @@
 (function() {
   var result = $array[$index];
   if ($check) {
     throw new Error(
         name + ": expected value of type \'$type\' at index " + ($index) +
         " but got " + (typeof result));
   }
   return result;
 })()''';
 }