Remove outdated deprecated_member_use ignores

lib/ui/hash_codes.dart

@@ -4,7 +4,6 @@
 part of dart.ui;
 
 // Examples can assume:
-// // ignore_for_file: deprecated_member_use
 // int foo = 0;
 // int bar = 0;
 // List<int> quux = <int>[];

lib/web_ui/test/engine/hash_codes_test.dart

@@ -16,10 +16,6 @@ void main() {
   internalBootstrapBrowserTest(() => testMain);
 }
 
-// Ignoring the deprecated member use because we're specifically testing
-// deprecated API.
-// ignore: deprecated_member_use
-
 void testMain() {
   test('hashValues and hashList can hash lots of huge values effectively', () {
     final int hashValueFromArgs = hashValues(

testing/dart/channel_buffers_test.dart

@@ -37,9 +37,6 @@ void main() {
       called = true;
     }
     buffers.push(channel, data, callback);
-    // Ignoring the deprecated member use because we're specifically testing
-    // deprecated API.
-    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       expect(drainedData, equals(data));
       expect(called, isFalse);
@@ -59,11 +56,6 @@ void main() {
     scheduleMicrotask(() { log.add('before drain, microtask'); });
     log.add('before drain');
 
-    // Ignoring the returned future because the completion of the drain is
-    // communicated using the `completer`.
-    // Ignoring the deprecated member use because we're specifically testing
-    // deprecated API.
-    // ignore: deprecated_member_use
     buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       log.add('callback');
       completer.complete();
@@ -89,9 +81,6 @@ void main() {
     _resize(buffers, channel, 0);
     buffers.push(channel, data, callback);
     bool didCall = false;
-    // Ignoring the deprecated member use because we're specifically testing
-    // deprecated API.
-    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       didCall = true;
     });
@@ -102,9 +91,6 @@ void main() {
     const String channel = 'foo';
     final ui.ChannelBuffers buffers = ui.ChannelBuffers();
     bool didCall = false;
-    // Ignoring the deprecated member use because we're specifically testing
-    // deprecated API.
-    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       didCall = true;
     });
@@ -125,9 +111,6 @@ void main() {
     buffers.push(channel, three, callback);
     buffers.push(channel, four, callback);
     int counter = 0;
-    // Ignoring the deprecated member use because we're specifically testing
-    // deprecated API.
-    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       switch (counter) {
         case 0:
@@ -153,9 +136,6 @@ void main() {
     buffers.push(channel, two, callback);
     _resize(buffers, channel, 1);
     int counter = 0;
-    // Ignoring the deprecated member use because we're specifically testing
-    // deprecated API.
-    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       switch (counter) {
         case 0: