Report messages instead of just printing.

pkg/front_end/lib/src/fasta/compiler_command_line.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.compiler_command_line;
 
 import 'dart:io' show exit;
 
+import 'package:kernel/target/targets.dart'
+    show Target, getTarget, TargetFlags, targets;
+
 import 'command_line.dart' show CommandLine, deprecated_argumentError;
 
 import 'compiler_context.dart' show CompilerContext;
 
-import 'package:kernel/target/targets.dart'
-    show Target, getTarget, TargetFlags, targets;
+import 'command_line_reporting.dart' as command_line_reporting;
 
 import 'fasta_codes.dart'
     show
+        LocatedMessage,
         Message,
         messageFastaUsageLong,
         messageFastaUsageShort,
         templateUnspecified;
 
+import 'severity.dart' show Severity;
+
 const Map<String, dynamic> optionSpecification = const <String, dynamic>{
   "--compile-sdk": Uri,
   "--fatal": ",",
   "--output": Uri,
   "-o": Uri,
   "--packages": Uri,
   "--platform": Uri,
   "--sdk": Uri,
   "--target": String,
   "-t": String,
@@ skipping 88 matching lines @@
   bool get nitsAreFatal => fatal.contains("nits");
 
   bool get strongMode => options.containsKey("--strong-mode");
 
   String get targetName {
     return options["-t"] ?? options["--target"] ?? "vm_fasta";
   }
 
   Target get target => options["target"];
 
+  void Function(LocatedMessage, Severity) get report {
+    return options["report"] ?? command_line_reporting.report;
+  }
+
+  void Function(Message, Severity) get reportWithoutLocation {
+    return options["reportWithoutLocation"] ??
+        command_line_reporting.reportWithoutLocation;
+  }
+
+  String Function(LocatedMessage, Severity) get format {
+    return options["format"] ?? command_line_reporting.format;
+  }
+
+  String Function(Message, Severity) get formatWithoutLocation {
+    return options["formatWithoutLocation"] ??
+        command_line_reporting.formatWithoutLocation;
+  }
+
   static dynamic withGlobalOptions(String programName, List<String> arguments,
       dynamic f(CompilerContext context)) {
     return CompilerContext.withGlobalOptions(
         new CompilerCommandLine(programName, arguments), f);
   }
 
   static CompilerCommandLine forRootContext() {
     return new CompilerCommandLine("", [""]);
   }
 }
@@ skipping 31 matching lines @@
   StringBuffer sb = new StringBuffer(basicUsage);
   if (summary != null) {
     sb.writeln();
     sb.writeln(summary);
     sb.writeln();
   }
   sb.write(options);
   // TODO(ahe): Don't use [templateUnspecified].
   return templateUnspecified.withArguments("$sb");
 }