Find diagnostic locations for use in new compiler API.

dart/frog/leg/apiimpl.dart

 // Copyright (c) 2012, 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('leg_apiimpl');
 
 #import('leg.dart', prefix: 'leg');
 #import('elements/elements.dart', prefix: 'leg');
 #import('tree/tree.dart', prefix: 'leg');
 #import('ssa/tracer.dart', prefix: 'ssa');
@@ skipping 41 matching lines @@
     return new leg.Script(uri, sourceFile);
   }
 
   bool run(Uri uri) {
     bool success = super.run(uri);
     for (final task in tasks) {
       log('${task.name} took ${task.timing}msec');
     }
     return success;
   }
+
+  void reportDiagnostic(leg.SourceSpan span, String message, bool fatal) {
+    if (span === null) {
+      handler(null, null, null, message, fatal);
+    } else {
+      handler(span.uri, span.begin, span.end, message, fatal);
+    }
+  }
 }