Use metadata annotation @patch for patch classes

runtime/lib/errors_patch.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.
 
 import 'dart:_internal' as internal;
 import 'dart:convert' show JSON;
 
-patch class Error {
-  /* patch */ static String _objectToString(Object object) {
+@patch class Error {
+  /* @patch */ static String _objectToString(Object object) {
     return Object._toString(object);
   }
 
-  /* patch */ static String _stringToSafeString(String string) {
+  /* @patch */ static String _stringToSafeString(String string) {
     return JSON.encode(string);
   }
 
-  /* patch */ StackTrace get stackTrace => _stackTrace;
+  /* @patch */ StackTrace get stackTrace => _stackTrace;
 
   StackTrace _stackTrace;
 }
 
 class _AssertionError extends Error implements AssertionError {
   _AssertionError._create(
       this._failedAssertion, this._url, this._line, this._column);
 
   static _throwNew(int assertionStart, int assertionEnd)
       native "AssertionError_throwNew";
@@ skipping 60 matching lines @@
 
   String toString() => _errorMsg;
 
   // Fields _url, _line, and _column are only used for debugging purposes.
   final String _url;
   final int _line;
   final int _column;
   final String _errorMsg;
 }
 
-patch class FallThroughError {
+@patch class FallThroughError {
   FallThroughError._create(this._url, this._line);
 
   static _throwNew(int case_clause_pos) native "FallThroughError_throwNew";
 
-  /* patch */ String toString() {
+  /* @patch */ String toString() {
     return "'$_url': Switch case fall-through at line $_line.";
   }
 
   // These new fields cannot be declared final, because a constructor exists
   // in the original version of this patched class.
   String _url;
   int _line;
 }
 
 class _InternalError {
   const _InternalError(this._msg);
   String toString() => "InternalError: '${_msg}'";
   final String _msg;
 }
 
-patch class UnsupportedError {
+@patch class UnsupportedError {
   static _throwNew(String msg) {
     throw new UnsupportedError(msg);
   }
 }
 
-patch class CyclicInitializationError {
+@patch class CyclicInitializationError {
   static _throwNew(String variableName) {
     throw new CyclicInitializationError(variableName);
   }
 }
 
-patch class AbstractClassInstantiationError {
+@patch class AbstractClassInstantiationError {
   AbstractClassInstantiationError._create(
       this._className, this._url, this._line);
 
   static _throwNew(int case_clause_pos, String className)
       native "AbstractClassInstantiationError_throwNew";
 
-  /* patch */ String toString() {
+  /* @patch */ String toString() {
     return "Cannot instantiate abstract class $_className: "
            "_url '$_url' line $_line";
   }
 
   // These new fields cannot be declared final, because a constructor exists
   // in the original version of this patched class.
   String _url;
   int _line;
 }
 
-patch class NoSuchMethodError {
+@patch class NoSuchMethodError {
   // The compiler emits a call to _throwNew when it cannot resolve a static
   // method at compile time. The receiver is actually the literal class of the
   // unresolved method.
   static void _throwNew(Object receiver,
                         String memberName,
                         int invocation_type,
                         List arguments,
                         List argumentNames,
                         List existingArgumentNames) {
     int numNamedArguments = argumentNames == null ? 0 : argumentNames.length;
@@ skipping 117 matching lines @@
         break;
       }
       case _InvocationMirror._TOP_LEVEL: {
         msg = "No top-level $type_str '$memberName'$args_message declared.";
         break;
       }
     }
     return "$msg\n\n";
   }
 
-  /* patch */ String toString() {
+  /* @patch */ String toString() {
     StringBuffer actual_buf = new StringBuffer();
     int i = 0;
     if (_arguments == null) {
       // Actual arguments unknown.
       // TODO(srdjan): Remove once arguments are passed for unresolvable
       // static methods.
       actual_buf.write("...");
     } else {
       for (; i < _arguments.length; i++) {
         if (i > 0) {
@@ skipping 47 matching lines @@
       msg_buf.write(
           "NoSuchMethodError: incorrect number of arguments passed to "
           "method named '$memberName'\n"
           "Receiver: $receiver_str\n"
           "Tried calling: $memberName($actualParameters)\n"
           "Found: $memberName($formalParameters)");
     }
     return msg_buf.toString();
   }
 }