Add option for outputting a deferred loading mapping.

pkg/compiler/lib/src/js_emitter/code_emitter_task.dart

 // Copyright (c) 2012, 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;
 
 const USE_NEW_EMITTER = const bool.fromEnvironment("dart2js.use.new.emitter");
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
@@ skipping 41 matching lines @@
     oldEmitter = new OldEmitter(compiler, namer, generateSourceMap, this);
     emitter = USE_NEW_EMITTER
         ? new new_js_emitter.Emitter(compiler, namer)
         : oldEmitter;
     nativeEmitter = new NativeEmitter(this);
   }
 
   jsAst.Expression isolateStaticClosureAccess(Element element) {
     return emitter.isolateStaticClosureAccess(element);
   }
-  
+
   jsAst.Expression isolateLazyInitializerAccess(Element element) {
     return emitter.isolateLazyInitializerAccess(element);
   }
-  
+
   jsAst.Expression generateEmbeddedGlobalAccess(String global) {
     return emitter.generateEmbeddedGlobalAccess(global);
   }
 
   jsAst.Expression constantReference(ConstantValue value) {
     return emitter.constantReference(value);
   }
 
   jsAst.Expression staticFieldAccess(Element e) {
     return emitter.staticFunctionAccess(e);
   }
-  
+
   jsAst.Expression staticFunctionAccess(Element e) {
     return emitter.staticFunctionAccess(e);
   }
-  
+
   jsAst.Expression classAccess(Element e) {
     return emitter.classAccess(e);
   }
-  
+
   jsAst.Expression typedefAccess(Element e) {
     return emitter.typedefAccess(e);
   }
 
   void registerReadTypeVariable(TypeVariableElement element) {
     readTypeVariables.add(element);
   }
 
   Set<ClassElement> interceptorsReferencedFromConstants() {
     Set<ClassElement> classes = new Set<ClassElement>();
@@ skipping 279 matching lines @@
 }
 
 abstract class Emitter {
   void emitProgram(Program program);
 
   jsAst.Expression isolateLazyInitializerAccess(Element element);
   jsAst.Expression isolateStaticClosureAccess(Element element);
   jsAst.Expression generateEmbeddedGlobalAccess(String global);
   jsAst.Expression constantReference(ConstantValue value);
   jsAst.PropertyAccess staticFunctionAccess(Element element);
-  
+
   // TODO(zarah): Split into more fine-grained accesses.
-  /// Generates access to the js constructor of the class represented by 
+  /// Generates access to the js constructor of the class represented by
   /// [element]
   jsAst.PropertyAccess classAccess(Element element);
   jsAst.PropertyAccess typedefAccess(Element element);
   jsAst.PropertyAccess staticFieldAccess(Element element);
-  
+
 
   int compareConstants(ConstantValue a, ConstantValue b);
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   void invalidateCaches();
 }