make FDE opt-in via the environment variable (#26898)

packages/flutter_tools/lib/src/desktop.dart

-// Copyright 2018 The Chromium Authors. All rights reserved.
+// Copyright 2019 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'base/file_system.dart';
 import 'base/platform.dart';
-import 'cache.dart';
 
-// Only launch or display desktop embedding devices if there is a sibling
-// FDE repository or a `FLUTTER_DESKTOP_EMBEDDING` environment variable which
-// contains a FDE repo.
-bool get hasFlutterDesktopRepository {
-  if (_hasFlutterDesktopRepository == null) {
-    final String desktopLocation = platform.environment['FLUTTER_DESKTOP_EMBEDDING'];
-    if (desktopLocation != null && desktopLocation.isNotEmpty) {
-      _hasFlutterDesktopRepository = fs.directory(desktopLocation)
-        .existsSync();
-    } else {
-      final Directory parent = fs.directory(Cache.flutterRoot).parent;
-      _hasFlutterDesktopRepository = parent
-        .childDirectory('flutter-desktop-embedding')
-        .existsSync();
-    }
-  }
-  return _hasFlutterDesktopRepository;
+// Only launch or display desktop embedding devices if
+// `FLUTTER_DESKTOP_EMBEDDING` environment variable is set to true.
+bool get flutterDesktopEnabled {
+  _flutterDesktopEnabled ??= platform.environment['FLUTTER_DESKTOP_EMBEDDING']?.toLowerCase() == 'true';
+  return _flutterDesktopEnabled;
 }
-bool _hasFlutterDesktopRepository;
+bool _flutterDesktopEnabled;

packages/flutter_tools/lib/src/linux/linux_workflow.dart

@@ -21,10 +21,10 @@ class LinuxWorkflow implements Workflow {
   bool get appliesToHostPlatform => platform.isLinux;
 
   @override
-  bool get canLaunchDevices => hasFlutterDesktopRepository;
+  bool get canLaunchDevices => flutterDesktopEnabled;
 
   @override
-  bool get canListDevices => hasFlutterDesktopRepository;
+  bool get canListDevices => flutterDesktopEnabled;
 
   @override
   bool get canListEmulators => false;

packages/flutter_tools/lib/src/macos/macos_workflow.dart

@@ -21,10 +21,10 @@ class MacOSWorkflow implements Workflow {
   bool get appliesToHostPlatform => platform.isMacOS;
 
   @override
-  bool get canLaunchDevices => hasFlutterDesktopRepository;
+  bool get canLaunchDevices => flutterDesktopEnabled;
 
   @override
-  bool get canListDevices => hasFlutterDesktopRepository;
+  bool get canListDevices => flutterDesktopEnabled;
 
   @override
   bool get canListEmulators => false;

packages/flutter_tools/lib/src/windows/windows_workflow.dart

@@ -21,10 +21,10 @@ class WindowsWorkflow implements Workflow {
   bool get appliesToHostPlatform => platform.isWindows;
 
   @override
-  bool get canLaunchDevices => hasFlutterDesktopRepository;
+  bool get canLaunchDevices => flutterDesktopEnabled;
 
   @override
-  bool get canListDevices => hasFlutterDesktopRepository;
+  bool get canListDevices => flutterDesktopEnabled;
 
   @override
   bool get canListEmulators => false;

packages/flutter_tools/test/linux/linux_workflow_test.dart

@@ -4,9 +4,7 @@
 
 import 'package:mockito/mockito.dart';
 import 'package:flutter_tools/src/linux/linux_workflow.dart';
-import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
-import 'package:flutter_tools/src/cache.dart';
 
 import '../src/common.dart';
 import '../src/context.dart';
@@ -14,8 +12,11 @@ import '../src/context.dart';
 void main() {
   group(LinuxWorkflow, () {
     final MockPlatform linux = MockPlatform();
+    final MockPlatform linuxWithFde = MockPlatform()
+      ..environment['FLUTTER_DESKTOP_EMBEDDING'] = 'true';
     final MockPlatform notLinux = MockPlatform();
     when(linux.isLinux).thenReturn(true);
+    when(linuxWithFde.isLinux).thenReturn(true);
     when(notLinux.isLinux).thenReturn(false);
 
     testUsingContext('Applies to linux platform', () {
@@ -29,30 +30,17 @@ void main() {
       Platform: () => notLinux,
     });
 
-    final MockFileSystem fileSystem = MockFileSystem();
-    final MockDirectory directory = MockDirectory();
-    Cache.flutterRoot = '';
-    when(fileSystem.directory(Cache.flutterRoot)).thenReturn(directory);
-    when(directory.parent).thenReturn(directory);
-    when(directory.childDirectory('flutter-desktop-embedding')).thenReturn(directory);
-    when(directory.existsSync()).thenReturn(true);
-
     testUsingContext('defaults', () {
       expect(linuxWorkflow.canListEmulators, false);
       expect(linuxWorkflow.canLaunchDevices, true);
       expect(linuxWorkflow.canListDevices, true);
     }, overrides: <Type, Generator>{
-      Platform: () => linux,
-      FileSystem: () => fileSystem,
+      Platform: () => linuxWithFde
     });
   });
 }
 
-class MockFileSystem extends Mock implements FileSystem {}
-
-class MockDirectory extends Mock implements Directory {}
-
 class MockPlatform extends Mock implements Platform {
   @override
-  Map<String, String> get environment => const <String, String>{};
+  final Map<String, String> environment = <String, String>{};
 }

packages/flutter_tools/test/macos/macos_workflow_test.dart

@@ -4,9 +4,7 @@
 
 import 'package:mockito/mockito.dart';
 
-import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
-import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/macos/macos_workflow.dart';
 
 import '../src/common.dart';
@@ -15,8 +13,11 @@ import '../src/context.dart';
 void main() {
   group(MacOSWorkflow, () {
     final MockPlatform mac = MockPlatform();
+    final MockPlatform macWithFde = MockPlatform()
+      ..environment['FLUTTER_DESKTOP_EMBEDDING'] = 'true';
     final MockPlatform notMac = MockPlatform();
     when(mac.isMacOS).thenReturn(true);
+    when(macWithFde.isMacOS).thenReturn(true);
     when(notMac.isMacOS).thenReturn(false);
 
     testUsingContext('Applies to mac platform', () {
@@ -30,30 +31,17 @@ void main() {
       Platform: () => notMac,
     });
 
-    final MockFileSystem fileSystem = MockFileSystem();
-    final MockDirectory directory = MockDirectory();
-    Cache.flutterRoot = '';
-    when(fileSystem.directory(Cache.flutterRoot)).thenReturn(directory);
-    when(directory.parent).thenReturn(directory);
-    when(directory.childDirectory('flutter-desktop-embedding')).thenReturn(directory);
-    when(directory.existsSync()).thenReturn(true);
-
     testUsingContext('defaults', () {
       expect(macOSWorkflow.canListEmulators, false);
       expect(macOSWorkflow.canLaunchDevices, true);
       expect(macOSWorkflow.canListDevices, true);
     }, overrides: <Type, Generator>{
-      Platform: () => mac,
-      FileSystem: () => fileSystem,
+      Platform: () => macWithFde,
     });
   });
 }
 
-class MockFileSystem extends Mock implements FileSystem {}
-
-class MockDirectory extends Mock implements Directory {}
-
 class MockPlatform extends Mock implements Platform {
   @override
-  Map<String, String> get environment => const <String, String>{};
+  Map<String, String> environment = <String, String>{};
 }

packages/flutter_tools/test/windows/windows_workflow_test.dart

@@ -4,9 +4,7 @@
 
 import 'package:mockito/mockito.dart';
 
-import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
-import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/windows/windows_workflow.dart';
 
 import '../src/common.dart';
@@ -15,8 +13,11 @@ import '../src/context.dart';
 void main() {
   group(WindowsWorkflow, () {
     final MockPlatform windows = MockPlatform();
+    final MockPlatform windowsWithFde = MockPlatform()
+      ..environment['FLUTTER_DESKTOP_EMBEDDING'] = 'true';
     final MockPlatform notWindows = MockPlatform();
     when(windows.isWindows).thenReturn(true);
+    when(windowsWithFde.isWindows).thenReturn(true);
     when(notWindows.isWindows).thenReturn(false);
 
     testUsingContext('Applies to windows platform', () {
@@ -30,30 +31,17 @@ void main() {
       Platform: () => notWindows,
     });
 
-    final MockFileSystem fileSystem = MockFileSystem();
-    final MockDirectory directory = MockDirectory();
-    Cache.flutterRoot = '';
-    when(fileSystem.directory(Cache.flutterRoot)).thenReturn(directory);
-    when(directory.parent).thenReturn(directory);
-    when(directory.childDirectory('flutter-desktop-embedding')).thenReturn(directory);
-    when(directory.existsSync()).thenReturn(true);
-
     testUsingContext('defaults', () {
       expect(windowsWorkflow.canListEmulators, false);
       expect(windowsWorkflow.canLaunchDevices, true);
       expect(windowsWorkflow.canListDevices, true);
     }, overrides: <Type, Generator>{
-      Platform: () => windows,
-      FileSystem: () => fileSystem,
+      Platform: () => windowsWithFde,
     });
   });
 }
 
-class MockFileSystem extends Mock implements FileSystem {}
-
-class MockDirectory extends Mock implements Directory {}
-
 class MockPlatform extends Mock implements Platform {
   @override
-  Map<String, String> get environment => const <String, String>{};
+  final Map<String, String> environment = <String, String>{};
 }