cleanup patch generation to preseve comments and remove @patch

test/generated_sdk/lib/core/string.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.
 
 part of dart.core;
 
 /**
  * A sequence of characters.
  *
  * A string can be either single or multiline. Single line strings are
@@ skipping 73 matching lines @@
  * [RegExp] to work with regular expressions.
  *
  * Also see:
 
  * * [Dart Cookbook](https://www.dartlang.org/docs/cookbook/#strings)
  * for String examples and recipes.
  * * [Dart Up and Running]
  * (https://www.dartlang.org/docs/dart-up-and-running/contents/ch03.html#ch03-strings-and-regular-expressions)
  */
 abstract class String implements Comparable<String>, Pattern {
-  @patch
+  /**
+   * Allocates a new String for the specified [charCodes].
+   *
+   * The [charCodes] can be UTF-16 code units or runes. If a char-code value is
+   * 16-bit, it is copied verbatim:
+   *
+   *     new String.fromCharCodes([68]); // 'D'
+   *
+   * If a char-code value is greater than 16-bits, it is decomposed into a
+   * surrogate pair:
+   *
+   *     var clef = new String.fromCharCodes([0x1D11E]);
+   *     clef.codeUnitAt(0); // 0xD834
+   *     clef.codeUnitAt(1); // 0xDD1E
+   *
+   * If [start] and [end] is provided, only the values of [charCodes]
+   * at positions from `start` to, but not including, `end`, are used.
+   * The `start` and `end` values must satisfy
+   * `0 <= start <= end <= charCodes.length`.
+   */
   factory String.fromCharCodes(Iterable<int> charCodes,
                                [int start = 0, int end]) {
     // If possible, recognize typed lists too.
     if (charCodes is! JSArray) {
       return _stringFromIterable(charCodes, start, end);
     }
 
     List list = charCodes;
     int len = list.length;
     if (start < 0 || start > len) {
       throw new RangeError.range(start, 0, len);
     }
     if (end == null) {
       end = len;
     } else if (end < start || end > len) {
       throw new RangeError.range(end, start, len);
     }
 
     if (start > 0 || end < len) {
       list = list.sublist(start, end);
     }
     return Primitives.stringFromCharCodes(list);
   }
 
-  @patch
+  /**
+   * Allocates a new String for the specified [charCode].
+   *
+   * If the [charCode] can be represented by a single UTF-16 code unit, the new
+   * string contains a single code unit. Otherwise, the [length] is 2 and
+   * the code units form a surrogate pair. See documentation for
+   * [fromCharCodes].
+   *
+   * Creating a String with half of a surrogate pair is allowed.
+   */
   factory String.fromCharCode(int charCode) {
     return Primitives.stringFromCharCode(charCode);
   }
 
-  @patch
+  /**
+   * Returns the string value of the environment declaration [name].
+   *
+   * Environment declarations are provided by the surrounding system compiling
+   * or running the Dart program. Declarations map a string key to a string
+   * value.
+   *
+   * If [name] is not declared in the environment, the result is instead
+   * [defaultValue].
+   *
+   * Example of getting a value:
+   *
+   *     const String.fromEnvironment("defaultFloo", defaultValue: "no floo")
+   *
+   * Example of checking whether a declaration is there at all:
+   *
+   *     var isDeclared = const String.fromEnvironment("maybeDeclared") != null;
+   */
   factory String.fromEnvironment(String name, {String defaultValue}) {
     throw new UnsupportedError(
         'String.fromEnvironment can only be used as a const constructor');
   }
 
   /**
    * Gets the character (as a single-code-unit [String]) at the given [index].
    *
    * The returned string represents exactly one UTF-16 code unit, which may be
    * half of a surrogate pair. A single member of a surrogate pair is an
@@ skipping 602 matching lines @@
         _position = position - 1;
         _currentCodePoint = _combineSurrogatePair(prevCodeUnit, codeUnit);
         return true;
       }
     }
     _position = position;
     _currentCodePoint = codeUnit;
     return true;
   }
 }