Add copyright header to generated analyzer files.

pkg/analyzer/lib/src/generated/sdk.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.sdk;
 
 import 'source.dart' show ContentCache, Source, UriKind;
 import 'engine.dart' show AnalysisContext;
 
 /**
  * Represents a single library in the SDK
@@ skipping 303 matching lines @@
 
   /**
    * Return the source representing the library with the given `dart:` URI, or `null` if
    * the given URI does not denote a library in this SDK.
    *
    * @param dartUri the URI of the library to be returned
    * @return the source representing the specified library
    */
   Source mapDartUri(String dartUri);
 }