Add the ability to deprecate Flatbuffer fields.

pkg/analyzer/tool/summary/idl_model.dart

Index: pkg/analyzer/tool/summary/idl_model.dart
diff --git a/pkg/analyzer/tool/summary/idl_model.dart b/pkg/analyzer/tool/summary/idl_model.dart
index a583d647a26fcdb0372c92cfcbba9152a60b2d6d..9ec248f994e41695ad4749531a100f0946ad8101 100644
--- a/pkg/analyzer/tool/summary/idl_model.dart
+++ b/pkg/analyzer/tool/summary/idl_model.dart
@@ -14,9 +14,9 @@ library analyzer.tool.summary.idl_model;
  */
 class ClassDeclaration extends Declaration {
   /**
-   * Fields defined in the class.
+   * All fields defined in the class, including deprecated ones.
    */
-  final List<FieldDeclaration> fields = <FieldDeclaration>[];
+  final List<FieldDeclaration> allFields = <FieldDeclaration>[];
 
   /**
    * Indicates whether the class has the `topLevel` annotation.
@@ -32,6 +32,12 @@ class ClassDeclaration extends Declaration {
   ClassDeclaration(
       String documentation, String name, this.isTopLevel, this.fileIdentifier)
       : super(documentation, name);
+
+  /**
+   * Get the non-deprecated fields defined in the class.
+   */
+  Iterable<FieldDeclaration> get fields =>
+      allFields.where((FieldDeclaration field) => !field.isDeprecated);
 }
 
 /**
@@ -86,7 +92,13 @@ class FieldDeclaration extends Declaration {
    */
   final int id;
 
-  FieldDeclaration(String documentation, String name, this.type, this.id)
+  /**
+   * Indicates whether the field is deprecated.
+   */
+  final bool isDeprecated;
+
+  FieldDeclaration(
+      String documentation, String name, this.type, this.id, this.isDeprecated)
       : super(documentation, name);
 }