Add *IndexSetIfNull methods to SemanticSendVisitor.

tests/compiler/dart2js/semantic_visitor_test_send_visitor.dart

Index: tests/compiler/dart2js/semantic_visitor_test_send_visitor.dart
diff --git a/tests/compiler/dart2js/semantic_visitor_test_send_visitor.dart b/tests/compiler/dart2js/semantic_visitor_test_send_visitor.dart
index cdbbe4199a8344a1954a619f183eceb98375eeb3..2187ba826aa5cfa308b5756e73e21e6c51ac8e54 100644
--- a/tests/compiler/dart2js/semantic_visitor_test_send_visitor.dart
+++ b/tests/compiler/dart2js/semantic_visitor_test_send_visitor.dart
@@ -3551,4 +3551,87 @@ class SemanticSendTestVisitor extends SemanticTestVisitor {
     super.visitUnresolvedTopLevelSetterSetIfNull(
         node, getter, element, rhs, arg);
   }
+
+  @override
+  visitIndexSetIfNull(
+      SendSet node,
+      Node receiver,
+      Node index,
+      Node rhs,
+      arg) {
+    visits.add(new Visit(
+        VisitKind.VISIT_INDEX_SET_IF_NULL,
+        receiver: receiver, index: index, rhs: rhs));
+    super.visitIndexSetIfNull(node, receiver, index, rhs, arg);
+  }
+
+  @override
+  visitSuperIndexSetIfNull(
+      SendSet node,
+      MethodElement getter,
+      MethodElement setter,
+      Node index,
+      Node rhs,
+      arg) {
+    visits.add(new Visit(
+        VisitKind.VISIT_SUPER_INDEX_SET_IF_NULL,
+        getter: getter, setter: setter, index: index, rhs: rhs));
+    super.visitSuperIndexSetIfNull(node, getter, setter, index, rhs, arg);
+  }
+
+  @override
+  visitUnresolvedSuperGetterIndexSetIfNull(
+      Send node,
+      Element element,
+      MethodElement setter,
+      Node index,
+      Node rhs,
+      arg) {
+    visits.add(new Visit(
+        VisitKind.VISIT_UNRESOLVED_SUPER_GETTER_INDEX_SET_IF_NULL,
+        setter: setter, index: index, rhs: rhs));
+    super.visitUnresolvedSuperGetterIndexSetIfNull(
+        node, element, setter, index, rhs, arg);
+  }
+
+  @override
+  visitUnresolvedSuperSetterIndexSetIfNull(
+      Send node,
+      MethodElement getter,
+      Element element,
+      Node index,
+      Node rhs,
+      arg) {
+    visits.add(new Visit(
+        VisitKind.VISIT_UNRESOLVED_SUPER_SETTER_INDEX_SET_IF_NULL,
+        getter: getter, index: index, rhs: rhs));
+    super.visitUnresolvedSuperSetterIndexSetIfNull(
+        node, getter, element, index, rhs, arg);
+  }
+
+  @override
+  visitUnresolvedSuperIndexSetIfNull(
+      Send node,
+      Element element,
+      Node index,
+      Node rhs,
+      arg) {
+    visits.add(new Visit(
+        VisitKind.VISIT_UNRESOLVED_SUPER_INDEX_SET_IF_NULL,
+        index: index, rhs: rhs));
+    super.visitUnresolvedSuperIndexSetIfNull(node, element, index, rhs, arg);
+  }
+
+  @override
+  errorInvalidIndexSetIfNull(
+      SendSet node,
+      ErroneousElement error,
+      Node index,
+      Node rhs,
+      arg) {
+    visits.add(new Visit(
+        VisitKind.ERROR_INVALID_SET_IF_NULL,
+        index: index, rhs: rhs));
+    super.visitUnresolvedSuperIndexSetIfNull(node, error, index, rhs, arg);
+  }
 }