Wrap dart:convert to track utf8 decode failures (#26650)

packages/flutter_tools/lib/src/android/android_device.dart

diff --git a/packages/flutter_tools/lib/src/android/android_device.dart b/packages/flutter_tools/lib/src/android/android_device.dart
index 9814318..9f9833f 100644
--- a/packages/flutter_tools/lib/src/android/android_device.dart
+++ b/packages/flutter_tools/lib/src/android/android_device.dart
@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:convert';
 
 import 'package:meta/meta.dart';
 
@@ -18,6 +17,7 @@
 import '../base/process.dart';
 import '../base/process_manager.dart';
 import '../build_info.dart';
+import '../convert.dart';
 import '../device.dart';
 import '../globals.dart';
 import '../project.dart';
@@ -681,7 +681,9 @@
       _timeOrigin = null;
     runCommand(device.adbCommandForDevice(args)).then<void>((Process process) {
       _process = process;
-      const Utf8Decoder decoder = Utf8Decoder(allowMalformed: true);
+      // We expect logcat streams to occasionally contain invalid utf-8,
+      // see: https://github.com/flutter/flutter/pull/8864.
+      const Utf8Decoder decoder = Utf8Decoder(reportErrors: false);
       _process.stdout.transform<String>(decoder).transform<String>(const LineSplitter()).listen(_onLine);
       _process.stderr.transform<String>(decoder).transform<String>(const LineSplitter()).listen(_onLine);
       _process.exitCode.whenComplete(() {

packages/flutter_tools/lib/src/android/android_sdk.dart

diff --git a/packages/flutter_tools/lib/src/android/android_sdk.dart b/packages/flutter_tools/lib/src/android/android_sdk.dart
index 39f90f5..f97cc5b 100644
--- a/packages/flutter_tools/lib/src/android/android_sdk.dart
+++ b/packages/flutter_tools/lib/src/android/android_sdk.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:convert';
-
 import 'package:meta/meta.dart';
 
 import '../base/common.dart';
@@ -15,6 +13,7 @@
 import '../base/process.dart';
 import '../base/process_manager.dart';
 import '../base/version.dart';
+import '../convert.dart';
 import '../globals.dart';
 import 'android_studio.dart' as android_studio;
 

packages/flutter_tools/lib/src/android/android_workflow.dart

diff --git a/packages/flutter_tools/lib/src/android/android_workflow.dart b/packages/flutter_tools/lib/src/android/android_workflow.dart
index dfbc083..00431f0 100644
--- a/packages/flutter_tools/lib/src/android/android_workflow.dart
+++ b/packages/flutter_tools/lib/src/android/android_workflow.dart
@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:convert';
 
 import '../base/common.dart';
 import '../base/context.dart';
@@ -14,6 +13,7 @@
 import '../base/user_messages.dart';
 import '../base/utils.dart';
 import '../base/version.dart';
+import '../convert.dart';
 import '../doctor.dart';
 import '../globals.dart';
 import 'android_sdk.dart';
@@ -256,13 +256,15 @@
       environment: androidSdk.sdkManagerEnv,
     );
     process.stdin.write('n\n');
+    // We expect logcat streams to occasionally contain invalid utf-8,
+    // see: https://github.com/flutter/flutter/pull/8864.
     final Future<void> output = process.stdout
-      .transform<String>(const Utf8Decoder(allowMalformed: true))
+      .transform<String>(const Utf8Decoder(reportErrors: false))
       .transform<String>(const LineSplitter())
       .listen(_handleLine)
       .asFuture<void>(null);
     final Future<void> errors = process.stderr
-      .transform<String>(const Utf8Decoder(allowMalformed: true))
+      .transform<String>(const Utf8Decoder(reportErrors: false))
       .transform<String>(const LineSplitter())
       .listen(_handleLine)
       .asFuture<void>(null);

packages/flutter_tools/lib/src/android/gradle.dart

diff --git a/packages/flutter_tools/lib/src/android/gradle.dart b/packages/flutter_tools/lib/src/android/gradle.dart
index a13d137..9cc182d 100644
--- a/packages/flutter_tools/lib/src/android/gradle.dart
+++ b/packages/flutter_tools/lib/src/android/gradle.dart
@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:convert';
 
 import 'package:archive/archive.dart';
 import 'package:meta/meta.dart';
@@ -20,6 +19,7 @@
 import '../base/utils.dart';
 import '../build_info.dart';
 import '../cache.dart';
+import '../convert.dart';
 import '../flutter_manifest.dart';
 import '../globals.dart';
 import '../project.dart';