dart2js: Implement frequency based naming.

pkg/compiler/lib/src/js_emitter/old_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.
 
 part of dart2js.js_emitter;
 
 
 class OldEmitter implements Emitter {
   final Compiler compiler;
   final CodeEmitterTask task;
@@ skipping 1633 matching lines @@
 
         outputs[outputUnit] = new jsAst.ArrayInitializer(parts);
       }
     }
 
     return outputs;
   }
 
   void finalizeTokensInAst(jsAst.Program main,
                            Iterable<jsAst.Program> deferredParts) {
-    task.metadataCollector.countTokensInAst(main);
-    deferredParts.forEach(task.metadataCollector.countTokensInAst);
+    jsAst.TokenCounter counter = new jsAst.TokenCounter();
+    counter.countTokens(main);
+    deferredParts.forEach(counter.countTokens);
     task.metadataCollector.finalizeTokens();
+    if (backend.namer is jsAst.TokenFinalizer) {
+      var finalizer = backend.namer;
+      finalizer.finalizeTokens();
+    }
   }
 
   int emitProgram(ProgramBuilder programBuilder) {
     Program program = programBuilder.buildProgram(
         storeFunctionTypesInMetadata: true);
 
     assembleProgram(program);
 
     // Construct the ASTs for all deferred output units.
     Map<OutputUnit, jsAst.Program> deferredParts =
@@ skipping 339 matching lines @@
     for (Element element in compiler.enqueuer.codegen.newlyEnqueuedElements) {
       if (element.isInstanceMember) {
         cachedClassBuilders.remove(element.enclosingClass);
 
         nativeEmitter.cachedBuilders.remove(element.enclosingClass);
 
       }
     }
   }
 }