support class native clause

pkg/front_end/messages.yaml

 # Copyright (c) 2017, 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.
 
 # Each entry in this map corresponds to a diagnostic message. Ideally, each
 # entry contains three parts:
 #
 # 1. A message template (template).
 #
 # 2. A suggestion for how to correct the problem (tip).
@@ skipping 562 matching lines @@
         internal stack trace from the compiler. Multiple kinds can be separated by
         commas, for example, --fatal=errors,warnings.
 
 FastaCLIArgumentRequired:
   template: "Expected value after '#name'."
 
 NamedFunctionExpression:
   template: "A function expression can't have a name."
   dart2jsCode: "*ignored*"
 
+NativeClauseShouldBeAnnotation:
+  template: "Native clause in this form is deprecated."
+  tip: "Try removing this native clause and adding @native() or @native('some-text-here') before the declaration."

[ahe, 2017/08/21 12:04:11]

'some-text-here' -> 'native name'.

[danrubel, 2017/08/22 01:35:28]

Fixed.

+  analyzerCode: NATIVE_CLAUSE_SHOULD_BE_ANNOTATION
+  dart2jsCode: "*fatal*"
+
 ReturnTypeFunctionExpression:
   template: "A function expression can't have a return type."
   dart2jsCode: "*ignored*"
 
 InternalProblemUnhandled:
   template: "Unhandled #string in #string2."
 
 InternalProblemUnimplemented:
   template: "Unimplemented #string."
 
@@ skipping 307 matching lines @@
 
 PackageNotFound:
   template: "Could not resolve the package '#name' in '#uri'."
 
 InvalidPackageUri:
   template: "Invalid package Uri '#uri':\n  #string."
 
 IntegerLiteralIsOutOfRange:
   template: "The integer literal #lexeme can't be represented in 64 bits."
   tip: "Try using BigInt (from 'dart:typed_data' library) if you need an integer larger than 9,223,372,036,854,775,807 or less than -9,223,372,036,854,775,808."