Make CompilerTask independent of compiler.

pkg/compiler/lib/src/js_backend/patch_resolver.dart

 // Copyright (c) 2014, 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.js_backend.patch_resolver;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../common/tasks.dart' show CompilerTask;
 import '../compiler.dart' show Compiler;
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../elements/modelx.dart';
 import '../tree/tree.dart';
 
 class PatchResolverTask extends CompilerTask {
-  PatchResolverTask(Compiler compiler) : super(compiler);
+  final Compiler compiler;
+  PatchResolverTask(Compiler compiler)
+      : compiler = compiler,
+        super(compiler.measurer);
+
+  DiagnosticReporter get reporter => compiler.reporter;
 
   Resolution get resolution => compiler.resolution;
 
   String get name => 'JavaScript patch resolver';
 
   FunctionElement resolveExternalFunction(FunctionElementX element) {
     if (element.isPatched) {
       FunctionElementX patch = element.patch;
       reporter.withCurrentElement(patch, () {
         patch.computeType(resolution);
@@ skipping 124 matching lines @@
           'originParameterCount': originSignature.optionalParameterCount,
           'patchParameterCount': patchSignature.optionalParameterCount
         });
       });
     } else {
       checkMatchingPatchParameters(origin, originSignature.optionalParameters,
           patchSignature.optionalParameters);
     }
   }
 }