Add accessor for getting target-specific constructor.

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

 // Copyright (c) 2016, 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 fasta.body_builder;
 
 import 'package:front_end/src/fasta/parser/parser.dart' show
     FormalParameterType,
     optional;
 
@@ skipping 2184 matching lines @@
   void nit(error, [int charOffset = -1]) {
     if (!showNits) return;
     String message = new InputError(uri, charOffset, error).format();
     print(message);
   }
 
   @override
   Expression buildCompileTimeError(error, [int charOffset = -1]) {
     String message = new InputError(uri, charOffset, error).format();
     print(message);
-    // TODO(ahe): Use a method on TargetImplementation for looking up the
-    // constructor.
-    final Constructor constructor = coreTypes.getCoreClass(
-        "dart:core", "_CompileTimeError").constructors.first;
-    return new Throw(new ConstructorInvocation(
-        constructor,
-        new Arguments(<Expression>[new StringLiteral(message)])));
+    Builder constructor = library.loader.getCompileTimeError();
+    return new Throw(
+        buildStaticInvocation(constructor.target,
+            new Arguments(<Expression>[new StringLiteral(message)]),
+            isConst: false)); // TODO(ahe): Make this const.
   }
 
   Statement buildCompileTimeErrorStatement(error, [int charOffset = -1]) {
     return new ExpressionStatement(buildCompileTimeError(error, charOffset));
   }
 
   @override
   Initializer buildCompileTimeErrorIntializer(error, [int charOffset = -1]) {
     return new LocalInitializer(
         new VariableDeclaration.forValue(
@@ skipping 479 matching lines @@
   } else if (node is TypeDeclarationBuilder) {
     return node.name;
   } else if (node is PrefixBuilder) {
     return node.name;
   } else if (node is ThisPropertyAccessor) {
     return node.name.name;
   } else {
     return internalError("Unhandled: ${node.runtimeType}");
   }
 }