Implement JsKernelToElementMap through KernelToElementMapBase

pkg/compiler/lib/src/js_emitter/full_emitter/emitter.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.
 
 library dart2js.js_emitter.full_emitter;
 
 import 'dart:collection' show HashMap;
 import 'dart:convert';
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
@@ skipping 58 matching lines @@
 
 class EmitterFactory implements js_emitter.EmitterFactory {
   final bool generateSourceMap;
 
   EmitterFactory({this.generateSourceMap});
 
   @override
   bool get supportsReflection => true;
 
   @override
-  Emitter createEmitter(
-      CodeEmitterTask task, Namer namer, ClosedWorld closedWorld) {
-    return new Emitter(task.compiler, namer, closedWorld, generateSourceMap,
-        task, task.sorter);
+  Emitter createEmitter(CodeEmitterTask task, Namer namer,
+      ClosedWorld closedWorld, Sorter sorter) {
+    return new Emitter(
+        task.compiler, namer, closedWorld, generateSourceMap, task, sorter);
   }
 }
 
 class Emitter extends js_emitter.EmitterBase {
   final Compiler compiler;
   final CodeEmitterTask task;
   final ClosedWorld _closedWorld;
 
   // The following fields will be set to copies of the program-builder's
   // collector.
@@ skipping 1871 matching lines @@
     // data.
     mapping["_comment"] = "This mapping shows which compiled `.js` files are "
         "needed for a given deferred library import.";
     mapping.addAll(compiler.deferredLoadTask.computeDeferredMap());
     compiler.outputProvider(
         compiler.options.deferredMapUri.path, '', OutputType.info)
       ..add(const JsonEncoder.withIndent("  ").convert(mapping))
       ..close();
   }
 }