Experimental `getDiagnostics` request (#24480).

pkg/analysis_server/tool/spec/to_html.dart

Index: pkg/analysis_server/tool/spec/to_html.dart
diff --git a/pkg/analysis_server/tool/spec/to_html.dart b/pkg/analysis_server/tool/spec/to_html.dart
index 63f8bb6743bb6d46b185409cce8539fda8391988..2ccf00e21a9555cb53a1a2df3ee016f195ba64c6 100644
--- a/pkg/analysis_server/tool/spec/to_html.dart
+++ b/pkg/analysis_server/tool/spec/to_html.dart
@@ -388,7 +388,9 @@ class ToHtmlVisitor extends HierarchicalApiVisitor
 
   @override
   void visitApi() {
-    definedTypes = api.types.keys.toSet();
+    Iterable<TypeDefinition> apiTypes =
+        api.types.where((TypeDefinition td) => !td.experimental);
+    definedTypes = apiTypes.map((TypeDefinition td) => td.name).toSet();
 
     html(() {
       translateHtml(api.html);
@@ -491,6 +493,9 @@ class ToHtmlVisitor extends HierarchicalApiVisitor
 
   @override
   void visitTypeDefinition(TypeDefinition typeDefinition) {
+    if (typeDefinition.experimental) {
+      return;
+    }
     dt('typeDefinition', () {
       anchor('type_${typeDefinition.name}', () {
         write('${typeDefinition.name}: ');