Add copyright header to generated analyzer files.

pkg/analyzer/lib/src/generated/source.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;
 
 import 'java_core.dart';
 import 'sdk.dart' show DartSdk;
 import 'engine.dart' show AnalysisContext;
 
 /**
@@ skipping 881 matching lines @@
     } else {
       int newStamp = JavaSystem.currentTimeMillis();
       int oldStamp = javaMapPut(_stampMap, source, newStamp);
       if (newStamp == oldStamp) {
         _stampMap[source] = newStamp + 1;
       }
       return javaMapPut(_contentMap, source, contents);
     }
   }
 }