dart2js: Remove oldEmitter field in emitter-task.

pkg/compiler/lib/src/use_unused_api.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.
 
 /// This file use methods that aren't used by dart2js.dart, but that we wish to
 /// keep anyway. This might be general API that isn't currently in use,
 /// debugging aids, or API only used for testing (see TODO below).
 
 library dart2js.use_unused_api;
 
@@ skipping 283 matching lines @@
       ..lookupLibrary(null);
   compiler.forgetElement(null);
   compiler.backend.constantCompilerTask.copyConstantValues(null);
 }
 
 useTypes() {
   new dart_types.ResolvedTypedefType(null, null, null).unalias(null);
 }
 
 useCodeEmitterTask(js_emitter.CodeEmitterTask codeEmitterTask) {
-  codeEmitterTask.oldEmitter.clearCspPrecompiledNodes();
-  codeEmitterTask.oldEmitter.
-      buildLazilyInitializedStaticField(null, isolateProperties: null);
+  js_emitter.OldEmitter fullEmitter = codeEmitterTask.emitter;
+  fullEmitter.clearCspPrecompiledNodes();
+  fullEmitter.buildLazilyInitializedStaticField(null, isolateProperties: null);
 }
 
 useScript(dart2jslib.Script script) {
   script.copyWithFile(null);
 }
 
 useProgramBuilder(program_builder.ProgramBuilder builder) {
   builder.buildMethodHackForIncrementalCompilation(null);
   builder.buildFieldsHackForIncrementalCompilation(null);
 }
@@ skipping 10 matching lines @@
 
 class TreeVisitor1 extends tree_ir.ExpressionVisitor1
                       with tree_ir.StatementVisitor1 {
   noSuchMethod(inv) {}
 }
 
 useTreeVisitors() {
   new TreeVisitor1().visitExpression(null, null);
   new TreeVisitor1().visitStatement(null, null);
 }