feat(xs-vat-worker): TextDecoder, HandledPromise before lockdown

packages/xs-vat-worker/src/bootstrap.js

@@ -1,5 +1,6 @@
 import './console-shim';
 import './text-shim';
 import './lockdown-shim';
+import '@agoric/eventual-send/shim';
 
 harden(console);

packages/xs-vat-worker/src/text-shim.js

@@ -1,12 +1,21 @@
+/* eslint-disable max-classes-per-file */
 /* eslint-disable class-methods-use-this */
 
 // Save this XS extension before SES shim deletes it.
 const { fromString } = ArrayBuffer;
+const { fromArrayBuffer } = String;
 
 class TextEncoder {
   encode(s) {
     return new Uint8Array(fromString(s));
   }
 }
 
+class TextDecoder {
+  decode(bs) {
+    return fromArrayBuffer(bs);
+  }
+}
+
 globalThis.TextEncoder = TextEncoder;
+globalThis.TextDecoder = TextDecoder;

packages/xs-vat-worker/test/test-boot-lockdown.js

@@ -37,10 +37,10 @@ test('bootstrap to SES lockdown', async t => {
     globalThis.send = msg => issueCommand(encoder.encode(JSON.stringify(msg)).buffer);
   `);
   await vat.evaluate(`
-    send([ typeof harden, typeof Compartment ]);
+    send([ typeof harden, typeof Compartment, typeof HandledPromise ]);
   `);
   await vat.close();
-  t.deepEqual(['["function","function"]'], messages);
+  t.deepEqual(['["function","function","function"]'], messages);
 });
 
 test('child compartment cannot access start powers', async t => {