Fix silly use of json.encode

Author: gspencergoog

lib/web_ui/test/keyboard_test.dart

@@ -18,14 +18,6 @@ void main() {
   internalBootstrapBrowserTest(() => testMain);
 }
 
-ByteData _toByteData(List<int> bytes) {
-  final ByteData byteData = ByteData(bytes.length);
-  for (int i = 0; i < bytes.length; i++) {
-    byteData.setUint8(i, bytes[i]);
-  }
-  return byteData;
-}
-
 void testMain() {
   group('Keyboard', () {
     /// Used to save and restore [ui.window.onPlatformMessage] after each test.
@@ -236,21 +228,13 @@ void testMain() {
     });
 
     test('prevents default when key is handled by the framework', () {
-      ByteData _toByteData(List<int> bytes) {
-        final ByteData byteData = ByteData(bytes.length);
-        for (int i = 0; i < bytes.length; i++) {
-          byteData.setUint8(i, bytes[i]);
-        }
-        return byteData;
-      }
-
       Keyboard.initialize();
 
       int count = 0;
       ui.window.onPlatformMessage = (String channel, ByteData data,
           ui.PlatformMessageResponseCallback callback) {
         count += 1;
-        ByteData response = _toByteData(utf8.encode(json.encode(<String, dynamic>{'handled': true})));
+        ByteData response = const JSONMessageCodec().encodeMessage(<String, dynamic>{'handled': true});
         callback(response);
       };
 
@@ -273,7 +257,7 @@ void testMain() {
       ui.window.onPlatformMessage = (String channel, ByteData data,
           ui.PlatformMessageResponseCallback callback) {
         count += 1;
-        ByteData response = _toByteData(utf8.encode(json.encode(<String, dynamic>{'handled': false})));
+        ByteData response = const JSONMessageCodec().encodeMessage(<String, dynamic>{'handled': false});
         callback(response);
       };
 
@@ -320,7 +304,7 @@ void testMain() {
       ui.window.onPlatformMessage = (String channel, ByteData data,
           ui.PlatformMessageResponseCallback callback) {
         count += 1;
-        ByteData response = _toByteData(utf8.encode(json.encode(<String, dynamic>{'handled': true})));
+        ByteData response = const JSONMessageCodec().encodeMessage(<String, dynamic>{'handled': true});
         callback(response);
       };