Remove code supporting incremental compilation in dart2js

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.
 
 library dart2js.js_emitter.code_emitter_task;
 
 import 'package:js_runtime/shared/embedded_names.dart' show JsBuiltin;
 
 import '../common.dart';
 import '../common/tasks.dart' show CompilerTask;
@@ skipping 156 matching lines @@
   void createEmitter(Namer namer, ClosedWorld closedWorld) {
     measure(() {
       _emitter = _emitterFactory.createEmitter(this, namer, closedWorld);
       metadataCollector = new MetadataCollector(compiler, _emitter);
       typeTestRegistry = new TypeTestRegistry(compiler, closedWorld);
     });
   }
 
   int assembleProgram(Namer namer, ClosedWorld closedWorld) {
     return measure(() {
-      emitter.invalidateCaches();
-
       Set<ClassEntity> rtiNeededClasses = _finalizeRti();
       ProgramBuilder programBuilder = new ProgramBuilder(
           compiler, namer, this, emitter, closedWorld, rtiNeededClasses);
       int size = emitter.emitProgram(programBuilder);
       // TODO(floitsch): we shouldn't need the `neededClasses` anymore.
       neededClasses = programBuilder.collector.neededClasses;
       return size;
     });
   }
 }
@@ skipping 54 matching lines @@
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   /// Returns the JS code for accessing the given [constant].
   jsAst.Expression constantReference(ConstantValue constant);
 
   /// Returns the JS template for the given [builtin].
   jsAst.Template templateForBuiltin(JsBuiltin builtin);
 
   /// Returns the size of the code generated for a given output [unit].
   int generatedSize(OutputUnit unit);
-
-  void invalidateCaches();
 }