dart2js: Rename metadataEmitter to metadataCollector and make it independent of 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
  * in classes) are ignored, since they can be treated as non-class elements.
  *
  * The code for the containing (used) methods must exist in the [:universe:].
  */
 class CodeEmitterTask extends CompilerTask {
   // TODO(floitsch): the code-emitter task should not need a namer.
   final Namer namer;
   final TypeTestRegistry typeTestRegistry;
   NativeEmitter nativeEmitter;
-  MetadataEmitter metadataEmitter;
+  MetadataCollector metadataCollector;
   OldEmitter oldEmitter;
   Emitter emitter;
 
   final Set<ClassElement> neededClasses = new Set<ClassElement>();
   final Map<OutputUnit, List<ClassElement>> outputClassLists =
       new Map<OutputUnit, List<ClassElement>>();
   final Map<OutputUnit, List<ConstantValue>> outputConstantLists =
       new Map<OutputUnit, List<ConstantValue>>();
   final Map<OutputUnit, List<Element>> outputStaticLists =
       new Map<OutputUnit, List<Element>>();
@@ skipping 19 matching lines @@
 
   CodeEmitterTask(Compiler compiler, Namer namer, bool generateSourceMap)
       : super(compiler),
         this.namer = namer,
         this.typeTestRegistry = new TypeTestRegistry(compiler) {
     oldEmitter = new OldEmitter(compiler, namer, generateSourceMap, this);
     emitter = USE_NEW_EMITTER
         ? new new_js_emitter.Emitter(compiler, namer)
         : oldEmitter;
     nativeEmitter = new NativeEmitter(this);
-    metadataEmitter = new MetadataEmitter();
-    metadataEmitter.emitter = oldEmitter;
+    metadataCollector = new MetadataCollector(compiler, emitter);
   }
 
   String get name => 'Code emitter';
 
   /// Returns the closure expression of a static function.
   jsAst.Expression isolateStaticClosureAccess(FunctionElement element) {
     return emitter.isolateStaticClosureAccess(element);
   }
 
   /// Returns the JS function that must be invoked to get the value of the
@@ skipping 388 matching lines @@
   jsAst.Expression typeAccess(Element e);
 
   /// Returns the JS expression representing a function that returns 'null'
   jsAst.Expression generateFunctionThatReturnsNull();
 
   int compareConstants(ConstantValue a, ConstantValue b);
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   void invalidateCaches();
 }