Remove the ability in dart2js to turn off syntax-only generic methods.

pkg/compiler/lib/src/compiler.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.
 
 library dart2js.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'cache_strategy.dart' show CacheStrategy;
@@ skipping 239 matching lines @@
     }
     enqueuer = backend.makeEnqueuer();
 
     if (options.dumpInfo && options.useStartupEmitter) {
       throw new ArgumentError(
           '--dump-info is not supported with the fast startup emitter');
     }
 
     tasks = [
       dietParser =
-          new DietParserTask(options, idGenerator, backend, reporter, measurer),
+          new DietParserTask(idGenerator, backend, reporter, measurer),
       scanner = createScannerTask(),
       serialization = new SerializationTask(this),
       libraryLoader = new LibraryLoaderTask(
           resolvedUriTranslator,
           options.compileOnly
               ? new _NoScriptLoader(this)
               : new _ScriptLoader(this),
           new _ElementScanner(scanner),
           serialization,
           this,
           environment,
           reporter,
           measurer),
-      parser = new ParserTask(this, options),
-      patchParser = new PatchParserTask(this, options),
+      parser = new ParserTask(this),
+      patchParser = new PatchParserTask(this),
       resolver = createResolverTask(),
       closureToClassMapper = new closureMapping.ClosureTask(this),
       checker = new TypeCheckerTask(this),
       globalInference = new GlobalTypeInferenceTask(this),
       constants = backend.constantCompilerTask,
       deferredLoadTask = new DeferredLoadTask(this),
       mirrorUsageAnalyzerTask = new MirrorUsageAnalyzerTask(this),
       // [enqueuer] is created earlier because it contains the resolution world
       // objects needed by other tasks.
       enqueuer,
       dumpInfoTask = new DumpInfoTask(this),
       selfTask = new GenericTask('self', measurer),
     ];
     if (options.resolveOnly) {
       serialization.supportSerialization = true;
     }
 
     _parsingContext =
-        new ParsingContext(reporter, options, parser, patchParser, backend);
+        new ParsingContext(reporter, parser, patchParser, backend);
 
     tasks.addAll(backend.tasks);
   }
 
   /// The world currently being computed by resolution. This forms a basis for
   /// the [inferenceWorld] and later the [closedWorld].
   OpenWorld get openWorld => _world;
 
   /// The closed world after resolution but currently refined by inference.
   ClosedWorldRefiner get inferenceWorld => _world;
@@ skipping 1943 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }