dart2js: start using the model in the old emitter.

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.
 
 part of dart2js.js_emitter;
 
 const USE_NEW_EMITTER = const bool.fromEnvironment("dart2js.use.new.emitter");
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
@@ skipping 397 matching lines @@
     computeNeededStaticNonFinalFields();
     computeNeededLibraries();
   }
 
   int assembleProgram() {
     return measure(() {
       emitter.invalidateCaches();
 
       computeAllNeededEntities();
 
-      Program program;
-      if (USE_NEW_EMITTER) {
-        program = new ProgramBuilder(compiler, namer, this).buildProgram();
-      }
+      Program program =
+          new ProgramBuilder(compiler, namer, this).buildProgram();
       return emitter.emitProgram(program);
     });
   }
 }
 
 abstract class Emitter {
   /// Emits [program] and returns the size of the generated output.
   int emitProgram(Program program);
 
   /// Returns the JS function that must be invoked to get the value of the
@@ skipping 31 matching lines @@
   jsAst.Expression typeAccess(Element e);
 
   /// Returns the JS constructor for the given closure class [e].
   jsAst.Expression closureClassConstructorAccess(ClosureClassElement e);
 
   int compareConstants(ConstantValue a, ConstantValue b);
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   void invalidateCaches();
 }