Improve detection of compile-time errors.

pkg/front_end/lib/src/fasta/fasta.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.outline;
+library fasta;
 
 import 'dart:async' show Future;
 
 import 'dart:convert' show JSON;
 
 import 'dart:io' show BytesBuilder, FileSystemEntity, exitCode;
 
 import 'package:kernel/binary/ast_to_binary.dart' show BinaryPrinter;
 
 import 'package:kernel/kernel.dart' show Program;
@@ skipping 165 matching lines @@
   final Ticker ticker = new Ticker(isVerbose: verbose);
   final DillTarget dillTarget = new DillTarget(ticker, uriTranslator);
   dillTarget.read(patchedSdk.resolve('platform.dill'));
   final KernelTarget kernelTarget = new KernelTarget(dillTarget, uriTranslator);
   try {
     kernelTarget.read(fileName);
     await dillTarget.writeOutline(null);
     program = await kernelTarget.writeOutline(null);
     program = await kernelTarget.writeProgram(null);
     if (kernelTarget.errors.isNotEmpty) {
-      return new CompilationResult.error(kernelTarget.errors
+      return new CompilationResult.errors(kernelTarget.errors
           .map((err) => err.toString())
           .toList(growable: false));
     }
   } on InputError catch (e) {
-    return new CompilationResult.error(<String>[e.format()]);
+    return new CompilationResult.error(e.format());
   }
 
   // Perform target-specific transformations.
   target.performModularTransformations(program);
   target.performGlobalTransformations(program);
 
   // Write the program to a list of bytes and return it.
   var sink = new ByteSink();
   new BinaryPrinter(sink).writeProgramFile(program);
   return new CompilationResult.ok(sink.builder.takeBytes());
 }
 
 // TODO(ahe): https://github.com/dart-lang/sdk/issues/28316
 class ByteSink implements Sink<List<int>> {
   final BytesBuilder builder = new BytesBuilder();
 
   void add(List<int> data) {
     builder.add(data);
   }
 
   void close() {
     // Nothing to do.
   }
 }