dart2js: add comments.

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 231 matching lines @@
     }
 
     // 4. Find all classes needed for rti.
     // It is important that this is the penultimate step, at this point,
     // neededClasses must only contain classes that have been resolved and
     // codegen'd. The rtiNeededClasses may contain additional classes, but
     // these are thought to not have been instantiated, so we neeed to be able
     // to identify them later and make sure we only emit "empty shells" without
     // fields, etc.
     typeTestEmitter.computeRtiNeededClasses();
+
+    // TODO(floitsch): either change the name, or get the rti-classes
+    // differently.
     typeTestEmitter.rtiNeededClasses.removeAll(neededClasses);
     // rtiNeededClasses now contains only the "empty shells".
     neededClasses.addAll(typeTestEmitter.rtiNeededClasses);
 
     // TODO(18175, floitsch): remove once issue 18175 is fixed.
     if (neededClasses.contains(backend.jsIntClass)) {
       neededClasses.add(compiler.intClass);
     }
     if (neededClasses.contains(backend.jsDoubleClass)) {
       neededClasses.add(compiler.doubleClass);
@@ skipping 88 matching lines @@
   void emitProgram(Program program);
 
   jsAst.Expression generateEmbeddedGlobalAccess(String global);
   jsAst.Expression constantReference(ConstantValue value);
 
   int compareConstants(ConstantValue a, ConstantValue b);
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   void invalidateCaches();
 }