cleanup patch generation to preseve comments and remove @patch

test/generated_sdk/lib/convert/json.dart

 // Copyright (c) 2013, 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.
 
 part of dart.convert;
 
 /**
  * Error thrown by JSON serialization if an object cannot be serialized.
  *
  * The [unsupportedObject] field holds that object that failed to be serialized.
@@ skipping 477 matching lines @@
    * If `this` was initialized with a reviver, then the parsing operation
    * invokes the reviver on every object or list property that has been parsed.
    * The arguments are the property name ([String]) or list index ([int]), and
    * the value is the parsed value. The return value of the reviver is used as
    * the value of that property instead the parsed value.
    *
    * Throws [FormatException] if the input is not valid JSON text.
    */
   dynamic convert(String input) => _parseJson(input, _reviver);
 
-  @patch
+  /**
+   * Starts a conversion from a chunked JSON string to its corresponding
+   * object.
+   *
+   * The output [sink] receives exactly one decoded element through `add`.
+   */
   StringConversionSink startChunkedConversion(Sink<Object> sink) {
     return new _JsonDecoderSink(_reviver, sink);
   }
 
   // Override the base-classes bind, to provide a better type.
   Stream<Object> bind(Stream<String> stream) => super.bind(stream);
 }
 
 // Internal optimized JSON parsing implementation.
-/**
- * Parses [json] and builds the corresponding parsed JSON value.
- *
- * Parsed JSON values Nare of the types [num], [String], [bool], [Null],
- * [List]s of parsed JSON values or [Map]s from [String] to parsed
- * JSON values.
- *
- * The optional [reviver] function, if provided, is called once for each object
- * or list property parsed. The arguments are the property name ([String]) or
- * list index ([int]), and the value is the parsed value.  The return value of
- * the reviver will be used as the value of that property instead of the parsed
- * value.  The top level value is passed to the reviver with the empty string as
- * a key.
- *
- * Throws [FormatException] if the input is not valid JSON text.
- */
-@patch
 _parseJson(String source, reviver(key, value)) {
   if (source is! String) throw new ArgumentError(source);
 
   var parsed;
   try {
     parsed = JS('=Object|JSExtendableArray|Null|bool|num|String',
                 'JSON.parse(#)',
                 source);
   } catch (e) {
     throw new FormatException(JS('String', 'String(#)', e));
@@ skipping 525 matching lines @@
         buffer.setRange(index, end, indent);
         index = end;
       } else {
         for (int i = 0; i < indentLength; i++) {
           writeByte(indent[i]);
         }
       }
     }
   }
 }