dart2js: patch file support cleanup

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 62 matching lines @@
 part 'declarations.dart';
 part 'deferred_output_unit_hash.dart';
 part 'setup_program_builder.dart';
 
 class EmitterFactory implements js_emitter.EmitterFactory {
   final bool generateSourceMap;
 
   EmitterFactory({this.generateSourceMap});
 
   @override
-  String get patchVersion => "full";
-
-  @override
   bool get supportsReflection => true;
 
   @override
   Emitter createEmitter(
       CodeEmitterTask task, Namer namer, ClosedWorld closedWorld) {
     return new Emitter(
         task.compiler, namer, closedWorld, generateSourceMap, task);
   }
 }
 
@@ skipping 1834 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();
   }
 }