Make CompilerTask independent of compiler.

pkg/compiler/lib/src/apiimpl.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 leg_apiimpl;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:package_config/packages.dart';
@@ skipping 13 matching lines @@
 import 'io/source_file.dart';
 import 'options.dart' show CompilerOptions;
 import 'platform_configuration.dart' as platform_configuration;
 import 'resolved_uri_translator.dart';
 import 'script.dart';
 import 'serialization/system.dart';
 
 /// Implements the [Compiler] using a [api.CompilerInput] for supplying the
 /// sources.
 class CompilerImpl extends Compiler {
+  final Measurer measurer;
   api.CompilerInput provider;
   api.CompilerDiagnostics handler;
   Packages packages;
 
   bool get mockableLibraryUsed => resolvedUriTranslator.isSet
       ? resolvedUriTranslator.mockableLibraryUsed
       : false;
 
   ForwardingResolvedUriTranslator resolvedUriTranslator;
 
   GenericTask userHandlerTask;
   GenericTask userProviderTask;
   GenericTask userPackagesDiscoveryTask;
 
   Uri get libraryRoot => options.platformConfigUri.resolve(".");
 
   CompilerImpl(this.provider, api.CompilerOutput outputProvider, this.handler,
       CompilerOptions options,
       {MakeBackendFuncion makeBackend, MakeReporterFunction makeReporter})
-      : resolvedUriTranslator = new ForwardingResolvedUriTranslator(),
+      // NOTE: allocating measurer is done upfront to ensure the wallclock is
+      // started before other computations.
+      : measurer = new Measurer(enableTaskMeasurements: options.verbose),
+        resolvedUriTranslator = new ForwardingResolvedUriTranslator(),
         super(
             options: options,
             outputProvider: outputProvider,
             environment: new _Environment(options.environment),
             makeBackend: makeBackend,
             makeReporter: makeReporter) {
     _Environment env = environment;
     env.compiler = this;
     tasks.addAll([
-      userHandlerTask = new GenericTask('Diagnostic handler', this),
-      userProviderTask = new GenericTask('Input provider', this),
-      userPackagesDiscoveryTask = new GenericTask('Package discovery', this),
+      userHandlerTask = new GenericTask('Diagnostic handler', measurer),
+      userProviderTask = new GenericTask('Input provider', measurer),
+      userPackagesDiscoveryTask =
+          new GenericTask('Package discovery', measurer),
     ]);
   }
 
   void log(message) {
     callUserHandler(
         null, null, null, null, message, api.Diagnostic.VERBOSE_INFO);
   }
 
   /**
    * Reads the script designated by [readableUri].
@@ skipping 314 matching lines @@
   }
 }
 
 /// For every 'dart:' library, a corresponding environment variable is set
 /// to "true". The environment variable's name is the concatenation of
 /// this prefix and the name (without the 'dart:'.
 ///
 /// For example 'dart:html' has the environment variable 'dart.library.html' set
 /// to "true".
 const String _dartLibraryEnvironmentPrefix = 'dart.library.';