Add Vector type to Kernel

pkg/kernel/lib/type_propagation/builder.dart

Index: pkg/kernel/lib/type_propagation/builder.dart
diff --git a/pkg/kernel/lib/type_propagation/builder.dart b/pkg/kernel/lib/type_propagation/builder.dart
index 2ac6e19b631d99390054b4991984e70bdd17572b..a7b4c9612e0ce26ab3be8e5bc96d285be748b6b2 100644
--- a/pkg/kernel/lib/type_propagation/builder.dart
+++ b/pkg/kernel/lib/type_propagation/builder.dart
@@ -1802,6 +1802,11 @@ class CovariantExternalTypeVisitor extends DartTypeVisitor<int> {
     return builder.nullNode;
   }
 
+  int visitVectorType(VectorType node) {
+    throw "Internal error: CovariantExternalTypeVisitor encountered VectorType "
+        "in native method signature";
+  }
+
   int visitInterfaceType(InterfaceType node) {
     int object = builder.getExternalInstanceVariable(node.classNode);
     for (int i = 0; i < node.typeArguments.length; ++i) {
@@ -1909,6 +1914,8 @@ class ContravariantExternalTypeVisitor extends DartTypeVisitor<Null> {
 
   visitVoidType(VoidType node) {}
 
+  visitVectorType(VectorType node) {}
+
   visitInterfaceType(InterfaceType node) {
     int escapePoint = builder.getInterfaceEscapeVariable(node.classNode);
     environment.addAssign(input, escapePoint);