Add copyright header to generated analyzer files.

pkg/analyzer/lib/src/generated/source_io.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.
+
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.source.io;
 
 import 'source.dart';
 import 'java_core.dart';
 import 'java_io.dart';
 import 'engine.dart' show AnalysisContext, AnalysisEngine;
 export 'source.dart';
@@ skipping 408 matching lines @@
     return null;
   }
 
   Source resolveAbsolute(ContentCache contentCache, Uri uri) {
     if (!isFileUri(uri)) {
       return null;
     }
     return new FileBasedSource.con1(contentCache, new JavaFile.fromUri(uri));
   }
 }