Restore visitLabelElement() and visitLocalVariableElement().

pkg/analyzer/lib/dart/element/visitor.dart

Index: pkg/analyzer/lib/dart/element/visitor.dart
diff --git a/pkg/analyzer/lib/dart/element/visitor.dart b/pkg/analyzer/lib/dart/element/visitor.dart
index 02bb94b72ae84dff023b8304a4aaf6d14c6c0628..dac2d23a7eee25191c1d1d77dae2a8abddac7d32 100644
--- a/pkg/analyzer/lib/dart/element/visitor.dart
+++ b/pkg/analyzer/lib/dart/element/visitor.dart
@@ -129,6 +129,9 @@ class GeneralizingElementVisitor<R> implements ElementVisitor<R> {
   R visitImportElement(ImportElement element) => visitElement(element);
 
   @override
+  R visitLabelElement(LabelElement element) => visitElement(element);
+
+  @override
   R visitLibraryElement(LibraryElement element) => visitElement(element);
 
   R visitLocalElement(LocalElement element) {
@@ -143,6 +146,10 @@ class GeneralizingElementVisitor<R> implements ElementVisitor<R> {
   }
 
   @override
+  R visitLocalVariableElement(LocalVariableElement element) =>
+      visitLocalElement(element);
+
+  @override
   R visitMethodElement(MethodElement element) =>
       visitExecutableElement(element);
 
@@ -250,12 +257,24 @@ class RecursiveElementVisitor<R> implements ElementVisitor<R> {
   }
 
   @override
+  R visitLabelElement(LabelElement element) {
+    element.visitChildren(this);
+    return null;
+  }
+
+  @override
   R visitLibraryElement(LibraryElement element) {
     element.visitChildren(this);
     return null;
   }
 
   @override
+  R visitLocalVariableElement(LocalVariableElement element) {
+    element.visitChildren(this);
+    return null;
+  }
+
+  @override
   R visitMethodElement(MethodElement element) {
     element.visitChildren(this);
     return null;
@@ -339,9 +358,15 @@ class SimpleElementVisitor<R> implements ElementVisitor<R> {
   R visitImportElement(ImportElement element) => null;
 
   @override
+  R visitLabelElement(LabelElement element) => null;
+
+  @override
   R visitLibraryElement(LibraryElement element) => null;
 
   @override
+  R visitLocalVariableElement(LocalVariableElement element) => null;
+
+  @override
   R visitMethodElement(MethodElement element) => null;
 
   @override
@@ -408,9 +433,15 @@ class ThrowingElementVisitor<R> implements ElementVisitor<R> {
   R visitImportElement(ImportElement element) => _throw(element);
 
   @override
+  R visitLabelElement(LabelElement element) => _throw(element);
+
+  @override
   R visitLibraryElement(LibraryElement element) => _throw(element);
 
   @override
+  R visitLocalVariableElement(LocalVariableElement element) => _throw(element);
+
+  @override
   R visitMethodElement(MethodElement element) => _throw(element);
 
   @override