Support for @JS() validation (#26225).

pkg/analyzer/lib/dart/element/element.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.
 
 /**
  * Defines the element model. The element model describes the semantic (as
  * opposed to syntactic) structure of Dart code. The syntactic structure of the
  * code is modeled by the [AST structure](../ast/ast.dart).
  *
  * The element model consists of two closely related kinds of objects: elements
@@ skipping 606 matching lines @@
    */
   int get id;
 
   /**
    * Return `true` if this element has an annotation of the form '@deprecated'
    * or '@Deprecated('..')'.
    */
   bool get isDeprecated;
 
   /**
+   * Return `true` if this element has an annotation of the form '@JS(..)'.
+   */
+  bool get isJS;
+
+  /**
    * Return `true` if this element has an annotation of the form '@override'.
    */
   bool get isOverride;
 
   /**
    * Return `true` if this element is private. Private elements are visible only
    * within the library in which they are declared.
    */
   bool get isPrivate;
 
@@ skipping 169 matching lines @@
    */
   Element get element;
 
   /**
    * Return `true` if this annotation marks the associated element as being
    * deprecated.
    */
   bool get isDeprecated;
 
   /**
+   * Return `true` if this annotation marks the associated element with the `JS`
+   * annotation.
+   */
+  bool get isJS;
+
+  /**
    * Return `true` if this annotation marks the associated member as requiring
    * overriding methods to call super.
    */
   bool get isMustCallSuper;
 
   /**
    * Return `true` if this annotation marks the associated method as being
    * expected to override an inherited method.
    */
   bool get isOverride;
@@ skipping 1153 matching lines @@
    */
   bool get isStatic;
 
   /**
    * Return the declared type of this variable, or `null` if the variable did
    * not have a declared type (such as if it was declared using the keyword
    * 'var').
    */
   DartType get type;
 }