Extract DiagnosticReporter implementation from Compiler.

pkg/compiler/lib/src/cps_ir/type_propagation.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.cps_ir.type_propagation;
 
 import 'optimizers.dart';
 
 import '../closure.dart' show
     ClosureClassElement;
 import '../common/names.dart' show
@@ skipping 337 matching lines @@
   final CpsFunctionCompiler _functionCompiler;
   final ConstantPropagationLattice _lattice;
   final dart2js.InternalErrorFunction _internalError;
   final Map<Variable, ConstantValue> _values = <Variable, ConstantValue>{};
   final TypeMaskSystem _typeSystem;
 
   TypePropagator(dart2js.Compiler compiler,
                  TypeMaskSystem typeSystem,
                  this._functionCompiler)
       : _compiler = compiler,
-        _internalError = compiler.internalError,
+        _internalError = compiler.reporter.internalError,
         _typeSystem = typeSystem,
         _lattice = new ConstantPropagationLattice(
             typeSystem,
             compiler.backend.constantSystem,
             compiler.types);
 
   @override
   void rewrite(FunctionDefinition root) {
     // Set all parent pointers.
     new ParentVisitor().visit(root);
@@ skipping 2277 matching lines @@
   processLetPrim(LetPrim node) {
     node.primitive.type = null;
     values[node.primitive] = null;
   }
 
   processLetMutable(LetMutable node) {
     node.variable.type = null;
     values[node.variable] = null;
   }
 }