Dart2js option to dump info about compilation

sdk/lib/_internal/compiler/implementation/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;
 
 /**
  * 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.
  *
@@ skipping 1158 matching lines @@
     for (String outputUnit in outputBuffers.keys) {
       ClassBuilder descriptor =
           descriptors.putIfAbsent(outputUnit, ()
               => new ClassBuilder());
       if (descriptor.properties.isEmpty) continue;
       bool isDeferred = outputUnit != "main";
       jsAst.Fun metadata = metadataEmitter.buildMetadataFunction(library);
 
       jsAst.ObjectInitializer initializers =
           descriptor.toObjectInitializer();
+      int sizeBefore = outputBuffers[outputUnit].length;
       outputBuffers[outputUnit]
           ..write('["${library.getLibraryName()}",$_')
           ..write('"${uri}",$_')
           ..write(metadata == null ? "" : jsAst.prettyPrint(metadata, compiler))
           ..write(isDeferred ? '[]' : '')
           ..write(',$_')
           ..write(namer.globalObjectFor(library))
           ..write(',$_')
           ..write(jsAst.prettyPrint(initializers, compiler))
           ..write(library == compiler.mainApp ? ',${n}1' : "")
           ..write('],$n');
+      int sizeAfter =  outputBuffers[outputUnit].length;
+      compiler.backend.
+          codeSizeCounter.countCode(library, sizeAfter - sizeBefore);
     }
   }
 
   String assembleProgram() {
     measure(() {
       // Compute the required type checks to know which classes need a
       // 'is$' method.
       typeTestEmitter.computeRequiredTypeChecks();
 
       computeNeededClasses();
@@ skipping 399 matching lines @@
   }
 
   bool isDeferred(Element element) {
     return compiler.deferredLoadTask.isDeferred(element);
   }
 
   bool get areAnyElementsDeferred {
     return compiler.deferredLoadTask.areAnyElementsDeferred;
   }
 }