Make CompilerTask independent of compiler.

pkg/compiler/lib/src/compile_time_constants.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.
 
 library dart2js.compile_time_constant_evaluator;
 
 import 'common.dart';
 import 'common/resolution.dart' show Resolution;
-import 'common/tasks.dart' show CompilerTask;
+import 'common/tasks.dart' show CompilerTask, Measurer;
 import 'compiler.dart' show Compiler;
 import 'constant_system_dart.dart';
 import 'constants/constant_system.dart';
 import 'constants/evaluation.dart';
 import 'constants/expressions.dart';
 import 'constants/values.dart';
 import 'core_types.dart' show CoreTypes;
 import 'dart_types.dart';
 import 'elements/elements.dart';
 import 'elements/modelx.dart'
@@ skipping 83 matching lines @@
   ConstantExpression getConstantForNode(Node node, TreeElements elements);
 
   /// Returns the compile-time constant value of [metadata].
   ConstantValue getConstantValueForMetadata(MetadataAnnotation metadata);
 }
 
 /// Interface for the task that compiles the constant environments for the
 /// frontend and backend interpretation of compile-time constants.
 abstract class ConstantCompilerTask extends CompilerTask
     implements ConstantCompiler {
-  ConstantCompilerTask(Compiler compiler) : super(compiler);
+  ConstantCompilerTask(Measurer measurer) : super(measurer);
 
   /// Copy all cached constant values from [task].
   ///
   /// This is a hack to support reuse cached compilers in memory_compiler.
   // TODO(johnniwinther): Remove this when values are computed from the
   // expressions.
   void copyConstantValues(ConstantCompilerTask task);
 }
 
 /**
@@ skipping 1239 matching lines @@
 class _CompilerEnvironment implements Environment {
   final Compiler compiler;
 
   _CompilerEnvironment(this.compiler);
 
   @override
   String readFromEnvironment(String name) {
     return compiler.fromEnvironment(name);
   }
 }