re-re-enable lint unnecessary_const (#20103)

diff --git a/packages/flutter_tools/lib/src/android/android_device.dart b/packages/flutter_tools/lib/src/android/android_device.dart
index f27497b..1a3c554 100644
--- a/packages/flutter_tools/lib/src/android/android_device.dart
+++ b/packages/flutter_tools/lib/src/android/android_device.dart

@@ -31,7 +31,7 @@
 enum _HardwareType { emulator, physical }
 
 /// Map to help our `isLocalEmulator` detection.
-const Map<String, _HardwareType> _knownHardware = const <String, _HardwareType>{
+const Map<String, _HardwareType> _knownHardware = <String, _HardwareType>{
   'goldfish': _HardwareType.emulator,
   'qcom': _HardwareType.physical,
   'ranchu': _HardwareType.emulator,
@@ -698,7 +698,7 @@
         _timeOrigin = null;
     runCommand(device.adbCommandForDevice(args)).then<Null>((Process process) {
       _process = process;
-      const Utf8Decoder decoder = const Utf8Decoder(allowMalformed: true);
+      const Utf8Decoder decoder = Utf8Decoder(allowMalformed: true);
       _process.stdout.transform(decoder).transform(const LineSplitter()).listen(_onLine);
       _process.stderr.transform(decoder).transform(const LineSplitter()).listen(_onLine);
       _process.exitCode.whenComplete(() {

diff --git a/packages/flutter_tools/lib/src/artifacts.dart b/packages/flutter_tools/lib/src/artifacts.dart
index f910386..53edf6e 100644
--- a/packages/flutter_tools/lib/src/artifacts.dart
+++ b/packages/flutter_tools/lib/src/artifacts.dart

@@ -292,7 +292,7 @@
   }
 
   String _genSnapshotPath() {
-    const List<String> clangDirs = const <String>['.', 'clang_x86', 'clang_x64', 'clang_i386'];
+    const List<String> clangDirs = <String>['.', 'clang_x86', 'clang_x64', 'clang_i386'];
     final String genSnapshotName = _artifactToFileName(Artifact.genSnapshot);
     for (String clangDir in clangDirs) {
       final String genSnapshotPath = fs.path.join(engineOutPath, clangDir, genSnapshotName);

diff --git a/packages/flutter_tools/lib/src/asset.dart b/packages/flutter_tools/lib/src/asset.dart
index 26e8fd9..e0d84eb 100644
--- a/packages/flutter_tools/lib/src/asset.dart
+++ b/packages/flutter_tools/lib/src/asset.dart

@@ -18,7 +18,7 @@
 import 'flutter_manifest.dart';
 import 'globals.dart';
 
-const AssetBundleFactory _kManifestFactory = const _ManifestAssetBundleFactory();
+const AssetBundleFactory _kManifestFactory = _ManifestAssetBundleFactory();
 
 /// Injected factory class for spawning [AssetBundle] instances.
 abstract class AssetBundleFactory {

diff --git a/packages/flutter_tools/lib/src/base/context.dart b/packages/flutter_tools/lib/src/base/context.dart
index fff6975..e4a20dd 100644
--- a/packages/flutter_tools/lib/src/base/context.dart
+++ b/packages/flutter_tools/lib/src/base/context.dart

@@ -170,7 +170,7 @@
 class _Key {
   const _Key();
 
-  static const _Key key = const _Key();
+  static const _Key key = _Key();
 
   @override
   String toString() => 'context';
@@ -180,5 +180,5 @@
 class _BoxedNull {
   const _BoxedNull();
 
-  static const _BoxedNull instance = const _BoxedNull();
+  static const _BoxedNull instance = _BoxedNull();
 }

diff --git a/packages/flutter_tools/lib/src/base/file_system.dart b/packages/flutter_tools/lib/src/base/file_system.dart
index a6f8c27..225dcb6 100644
--- a/packages/flutter_tools/lib/src/base/file_system.dart
+++ b/packages/flutter_tools/lib/src/base/file_system.dart

@@ -16,7 +16,7 @@
 export 'package:file/local.dart';
 
 const String _kRecordingType = 'file';
-const FileSystem _kLocalFs = const LocalFileSystem();
+const FileSystem _kLocalFs = LocalFileSystem();
 
 /// Currently active implementation of the file system.
 ///

diff --git a/packages/flutter_tools/lib/src/base/io.dart b/packages/flutter_tools/lib/src/base/io.dart
index c09041f..be2dcb2 100644
--- a/packages/flutter_tools/lib/src/base/io.dart
+++ b/packages/flutter_tools/lib/src/base/io.dart

@@ -116,12 +116,12 @@
   @visibleForTesting
   const ProcessSignal(this._delegate);
 
-  static const ProcessSignal SIGWINCH = const _PosixProcessSignal._(io.ProcessSignal.sigwinch);
-  static const ProcessSignal SIGTERM = const _PosixProcessSignal._(io.ProcessSignal.sigterm);
-  static const ProcessSignal SIGUSR1 = const _PosixProcessSignal._(io.ProcessSignal.sigusr1);
-  static const ProcessSignal SIGUSR2 = const _PosixProcessSignal._(io.ProcessSignal.sigusr2);
-  static const ProcessSignal SIGINT =  const ProcessSignal(io.ProcessSignal.sigint);
-  static const ProcessSignal SIGKILL =  const ProcessSignal(io.ProcessSignal.sigkill);
+  static const ProcessSignal SIGWINCH = _PosixProcessSignal._(io.ProcessSignal.sigwinch);
+  static const ProcessSignal SIGTERM = _PosixProcessSignal._(io.ProcessSignal.sigterm);
+  static const ProcessSignal SIGUSR1 = _PosixProcessSignal._(io.ProcessSignal.sigusr1);
+  static const ProcessSignal SIGUSR2 = _PosixProcessSignal._(io.ProcessSignal.sigusr2);
+  static const ProcessSignal SIGINT =  ProcessSignal(io.ProcessSignal.sigint);
+  static const ProcessSignal SIGKILL =  ProcessSignal(io.ProcessSignal.sigkill);
 
   final io.ProcessSignal _delegate;
 

diff --git a/packages/flutter_tools/lib/src/base/os.dart b/packages/flutter_tools/lib/src/base/os.dart
index f452b79..1faa3d3 100644
--- a/packages/flutter_tools/lib/src/base/os.dart
+++ b/packages/flutter_tools/lib/src/base/os.dart

@@ -59,7 +59,7 @@
   ///
   /// If available, the detailed version of the OS is included.
   String get name {
-    const Map<String, String> osNames = const <String, String>{
+    const Map<String, String> osNames = <String, String>{
       'macos': 'Mac OS',
       'linux': 'Linux',
       'windows': 'Windows'

diff --git a/packages/flutter_tools/lib/src/base/platform.dart b/packages/flutter_tools/lib/src/base/platform.dart
index c781499..1a45a08 100644
--- a/packages/flutter_tools/lib/src/base/platform.dart
+++ b/packages/flutter_tools/lib/src/base/platform.dart

@@ -11,7 +11,7 @@
 
 export 'package:platform/platform.dart';
 
-const Platform _kLocalPlatform = const LocalPlatform();
+const Platform _kLocalPlatform = LocalPlatform();
 const String _kRecordingType = 'platform';
 
 Platform get platform => context[Platform] ?? _kLocalPlatform;

diff --git a/packages/flutter_tools/lib/src/base/process.dart b/packages/flutter_tools/lib/src/base/process.dart
index a3dca75..6eceade 100644
--- a/packages/flutter_tools/lib/src/base/process.dart
+++ b/packages/flutter_tools/lib/src/base/process.dart

@@ -33,19 +33,19 @@
 
   /// The stage before the invocation recording (if one exists) is serialized
   /// to disk. Tasks performed during this stage *will* be recorded.
-  static const ShutdownStage STILL_RECORDING = const ShutdownStage._(1);
+  static const ShutdownStage STILL_RECORDING = ShutdownStage._(1);
 
   /// The stage during which the invocation recording (if one exists) will be
   /// serialized to disk. Invocations performed after this stage will not be
   /// recorded.
-  static const ShutdownStage SERIALIZE_RECORDING = const ShutdownStage._(2);
+  static const ShutdownStage SERIALIZE_RECORDING = ShutdownStage._(2);
 
   /// The stage during which a serialized recording will be refined (e.g.
   /// cleansed for tests, zipped up for bug reporting purposes, etc.).
-  static const ShutdownStage POST_PROCESS_RECORDING = const ShutdownStage._(3);
+  static const ShutdownStage POST_PROCESS_RECORDING = ShutdownStage._(3);
 
   /// The stage during which temporary files and directories will be deleted.
-  static const ShutdownStage CLEANUP = const ShutdownStage._(4);
+  static const ShutdownStage CLEANUP = ShutdownStage._(4);
 
   @override
   int compareTo(ShutdownStage other) => priority.compareTo(other.priority);

diff --git a/packages/flutter_tools/lib/src/base/process_manager.dart b/packages/flutter_tools/lib/src/base/process_manager.dart
index 18b5703..5486e7c 100644
--- a/packages/flutter_tools/lib/src/base/process_manager.dart
+++ b/packages/flutter_tools/lib/src/base/process_manager.dart

@@ -13,7 +13,7 @@
 import 'process.dart';
 
 const String _kRecordingType = 'process';
-const ProcessManager _kLocalProcessManager = const LocalProcessManager();
+const ProcessManager _kLocalProcessManager = LocalProcessManager();
 
 /// The active process manager.
 ProcessManager get processManager => context[ProcessManager] ?? _kLocalProcessManager;
@@ -27,7 +27,7 @@
 /// subdirectory.
 RecordingProcessManager getRecordingProcessManager(String location) {
   final Directory dir = getRecordingSink(location, _kRecordingType);
-  const ProcessManager delegate = const LocalProcessManager();
+  const ProcessManager delegate = LocalProcessManager();
   final RecordingProcessManager manager = new RecordingProcessManager(delegate, dir);
   addShutdownHook(() async {
     await manager.flush(finishRunningProcesses: true);

diff --git a/packages/flutter_tools/lib/src/base/terminal.dart b/packages/flutter_tools/lib/src/base/terminal.dart
index 468c16f..7f3ece3 100644
--- a/packages/flutter_tools/lib/src/base/terminal.dart
+++ b/packages/flutter_tools/lib/src/base/terminal.dart

@@ -33,7 +33,7 @@
 
   /// Setting the line mode can throw for some terminals (with "Operation not
   /// supported on socket"), but the error can be safely ignored.
-  static const List<int> _lineModeIgnorableErrors = const <int>[
+  static const List<int> _lineModeIgnorableErrors = <int>[
     _EBADF,
     _ENXIO,
     _ENOTTY,

diff --git a/packages/flutter_tools/lib/src/base/utils.dart b/packages/flutter_tools/lib/src/base/utils.dart
index f13c9c9..44e9c62 100644
--- a/packages/flutter_tools/lib/src/base/utils.dart
+++ b/packages/flutter_tools/lib/src/base/utils.dart

@@ -15,7 +15,7 @@
 import 'file_system.dart';
 import 'platform.dart';
 
-const BotDetector _kBotDetector = const BotDetector();
+const BotDetector _kBotDetector = BotDetector();
 
 class BotDetector {
   const BotDetector();

diff --git a/packages/flutter_tools/lib/src/build_info.dart b/packages/flutter_tools/lib/src/build_info.dart
index 1c3a969..4f463f3 100644
--- a/packages/flutter_tools/lib/src/build_info.dart
+++ b/packages/flutter_tools/lib/src/build_info.dart

@@ -71,9 +71,9 @@
   /// On Xcode builds it is used as CFBundleShortVersionString,
   final String buildName;
 
-  static const BuildInfo debug = const BuildInfo(BuildMode.debug, null);
-  static const BuildInfo profile = const BuildInfo(BuildMode.profile, null);
-  static const BuildInfo release = const BuildInfo(BuildMode.release, null);
+  static const BuildInfo debug = BuildInfo(BuildMode.debug, null);
+  static const BuildInfo profile = BuildInfo(BuildMode.profile, null);
+  static const BuildInfo release = BuildInfo(BuildMode.release, null);
 
   /// Returns whether a debug build is requested.
   ///
@@ -174,7 +174,7 @@
 }
 
 /// The default set of iOS device architectures to build for.
-const List<IOSArch> defaultIOSArchs = const <IOSArch>[
+const List<IOSArch> defaultIOSArchs = <IOSArch>[
   IOSArch.arm64,
 ];
 

diff --git a/packages/flutter_tools/lib/src/cache.dart b/packages/flutter_tools/lib/src/cache.dart
index 326c24e..716d33c 100644
--- a/packages/flutter_tools/lib/src/cache.dart
+++ b/packages/flutter_tools/lib/src/cache.dart

@@ -29,7 +29,7 @@
     }
   }
 
-  static const List<String> _hostsBlockedInChina = const <String> [
+  static const List<String> _hostsBlockedInChina = <String> [
     'storage.googleapis.com',
   ];
 

diff --git a/packages/flutter_tools/lib/src/commands/analyze_base.dart b/packages/flutter_tools/lib/src/commands/analyze_base.dart
index 9464d3b..5e07adc 100644
--- a/packages/flutter_tools/lib/src/commands/analyze_base.dart
+++ b/packages/flutter_tools/lib/src/commands/analyze_base.dart

@@ -116,7 +116,7 @@
 
 class PackageDependencyTracker {
   /// Packages whose source is defined in the vended SDK.
-  static const List<String> _vendedSdkPackages = const <String>['analyzer', 'front_end', 'kernel'];
+  static const List<String> _vendedSdkPackages = <String>['analyzer', 'front_end', 'kernel'];
 
   // This is a map from package names to objects that track the paths
   // involved (sources and targets).

diff --git a/packages/flutter_tools/lib/src/commands/update_packages.dart b/packages/flutter_tools/lib/src/commands/update_packages.dart
index aca3411..e3925f8 100644
--- a/packages/flutter_tools/lib/src/commands/update_packages.dart
+++ b/packages/flutter_tools/lib/src/commands/update_packages.dart

@@ -25,7 +25,7 @@
 /// ```
 ///   'linter': '0.1.35', // TODO(yjbanov): https://github.com/dart-lang/linter/issues/824
 /// ```
-const Map<String, String> _kManuallyPinnedDependencies = const <String, String>{
+const Map<String, String> _kManuallyPinnedDependencies = <String, String>{
   // Add pinned packages here.
   'mockito': '3.0.0-beta', // TODO(aam): https://github.com/dart-lang/mockito/issues/110
   'matcher': '0.12.2+1', // TODO(ianh): https://github.com/flutter/flutter/issues/18608, https://github.com/dart-lang/matcher/pull/88

diff --git a/packages/flutter_tools/lib/src/dart/sdk.dart b/packages/flutter_tools/lib/src/dart/sdk.dart
index b1af8d9..833fdec 100644
--- a/packages/flutter_tools/lib/src/dart/sdk.dart
+++ b/packages/flutter_tools/lib/src/dart/sdk.dart

@@ -12,7 +12,7 @@
 }
 
 /// The required Dart language flags
-const List<String> dartVmFlags = const <String>[];
+const List<String> dartVmFlags = <String>[];
 
 /// Return the platform specific name for the given Dart SDK binary. So, `pub`
 /// ==> `pub.bat`. The default SDK location can be overridden with a specified

diff --git a/packages/flutter_tools/lib/src/device.dart b/packages/flutter_tools/lib/src/device.dart
index 32f3d9b..407a269 100644
--- a/packages/flutter_tools/lib/src/device.dart
+++ b/packages/flutter_tools/lib/src/device.dart

@@ -129,8 +129,8 @@
 abstract class PollingDeviceDiscovery extends DeviceDiscovery {
   PollingDeviceDiscovery(this.name);
 
-  static const Duration _pollingInterval = const Duration(seconds: 4);
-  static const Duration _pollingTimeout = const Duration(seconds: 30);
+  static const Duration _pollingInterval = Duration(seconds: 4);
+  static const Duration _pollingTimeout = Duration(seconds: 30);
 
   final String name;
   ItemListNotifier<Device> _items;

diff --git a/packages/flutter_tools/lib/src/emulator.dart b/packages/flutter_tools/lib/src/emulator.dart
index a860c42..e0e144a 100644
--- a/packages/flutter_tools/lib/src/emulator.dart
+++ b/packages/flutter_tools/lib/src/emulator.dart

@@ -127,7 +127,7 @@
     );
   }
 
-  static const List<String> preferredDevices = const <String>[
+  static const List<String> preferredDevices = <String>[
     'pixel',
     'pixel_xl',
   ];

diff --git a/packages/flutter_tools/lib/src/ios/code_signing.dart b/packages/flutter_tools/lib/src/ios/code_signing.dart
index 0da85d2..6797a6e 100644
--- a/packages/flutter_tools/lib/src/ios/code_signing.dart
+++ b/packages/flutter_tools/lib/src/ios/code_signing.dart

@@ -118,7 +118,7 @@
     return null;
 
   const List<String> findIdentityCommand =
-      const <String>['security', 'find-identity', '-p', 'codesigning', '-v'];
+      <String>['security', 'find-identity', '-p', 'codesigning', '-v'];
   final List<String> validCodeSigningIdentities = runCheckedSync(findIdentityCommand)
       .split('\n')
       .map<String>((String outputLine) {

diff --git a/packages/flutter_tools/lib/src/ios/devices.dart b/packages/flutter_tools/lib/src/ios/devices.dart
index 3ea48a1..14b1b91 100644
--- a/packages/flutter_tools/lib/src/ios/devices.dart
+++ b/packages/flutter_tools/lib/src/ios/devices.dart

@@ -26,7 +26,7 @@
     'To work with iOS devices, please install ideviceinstaller. To install, run:\n'
     'brew install ideviceinstaller.';
 
-const Duration kPortForwardTimeout = const Duration(seconds: 10);
+const Duration kPortForwardTimeout = Duration(seconds: 10);
 
 class IOSDeploy {
   const IOSDeploy();
@@ -530,7 +530,7 @@
   @override
   List<ForwardedPort> get forwardedPorts => _forwardedPorts;
 
-  static const Duration _kiProxyPortForwardTimeout = const Duration(seconds: 1);
+  static const Duration _kiProxyPortForwardTimeout = Duration(seconds: 1);
 
   @override
   Future<int> forward(int devicePort, {int hostPort}) async {

diff --git a/packages/flutter_tools/lib/src/ios/simulators.dart b/packages/flutter_tools/lib/src/ios/simulators.dart
index 16fcbc7..7e2de4e 100644
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart

@@ -145,10 +145,10 @@
 
   final String name;
 
-  static const SimControlListSection devices = const SimControlListSection._('devices');
-  static const SimControlListSection devicetypes = const SimControlListSection._('devicetypes');
-  static const SimControlListSection runtimes = const SimControlListSection._('runtimes');
-  static const SimControlListSection pairs = const SimControlListSection._('pairs');
+  static const SimControlListSection devices = SimControlListSection._('devices');
+  static const SimControlListSection devicetypes = SimControlListSection._('devicetypes');
+  static const SimControlListSection runtimes = SimControlListSection._('runtimes');
+  static const SimControlListSection pairs = SimControlListSection._('pairs');
 }
 
 /// A simulated device type.
@@ -668,7 +668,7 @@
     return v1.compareTo(v2);
 
   // Sorted in the least preferred first order.
-  const List<String> qualifiers = const <String>['-Plus', '', 's-Plus', 's'];
+  const List<String> qualifiers = <String>['-Plus', '', 's-Plus', 's'];
 
   final int q1 = qualifiers.indexOf(m1[2]);
   final int q2 = qualifiers.indexOf(m2[2]);

diff --git a/packages/flutter_tools/lib/src/test/flutter_platform.dart b/packages/flutter_tools/lib/src/test/flutter_platform.dart
index 8c69a43..ea41b90 100644
--- a/packages/flutter_tools/lib/src/test/flutter_platform.dart
+++ b/packages/flutter_tools/lib/src/test/flutter_platform.dart

@@ -25,12 +25,12 @@
 
 /// The timeout we give the test process to connect to the test harness
 /// once the process has entered its main method.
-const Duration _kTestStartupTimeout = const Duration(minutes: 1);
+const Duration _kTestStartupTimeout = Duration(minutes: 1);
 
 /// The timeout we give the test process to start executing Dart code. When the
 /// CPU is under severe load, this can take a while, but it's not indicative of
 /// any problem with Flutter, so we give it a large timeout.
-const Duration _kTestProcessTimeout = const Duration(minutes: 5);
+const Duration _kTestProcessTimeout = Duration(minutes: 5);
 
 /// Message logged by the test process to signal that its main method has begun
 /// execution.

diff --git a/packages/flutter_tools/lib/src/version.dart b/packages/flutter_tools/lib/src/version.dart
index 28e1328..45cd4a7 100644
--- a/packages/flutter_tools/lib/src/version.dart
+++ b/packages/flutter_tools/lib/src/version.dart

@@ -206,20 +206,20 @@
   /// The amount of time we wait before pinging the server to check for the
   /// availability of a newer version of Flutter.
   @visibleForTesting
-  static const Duration kCheckAgeConsideredUpToDate = const Duration(days: 3);
+  static const Duration kCheckAgeConsideredUpToDate = Duration(days: 3);
 
   /// We warn the user if the age of their Flutter installation is greater than
   /// this duration.
   ///
   /// This is set to 5 weeks because releases are currently around every 4 weeks.
   @visibleForTesting
-  static const Duration kVersionAgeConsideredUpToDate = const Duration(days: 35);
+  static const Duration kVersionAgeConsideredUpToDate = Duration(days: 35);
 
   /// The amount of time we wait between issuing a warning.
   ///
   /// This is to avoid annoying users who are unable to upgrade right away.
   @visibleForTesting
-  static const Duration kMaxTimeSinceLastWarning = const Duration(days: 1);
+  static const Duration kMaxTimeSinceLastWarning = Duration(days: 1);
 
   /// The amount of time we pause for to let the user read the message about
   /// outdated Flutter installation.
@@ -418,7 +418,7 @@
     if (newTimeWarningWasPrinted != null)
       jsonData['lastTimeWarningWasPrinted'] = '$newTimeWarningWasPrinted';
 
-    const JsonEncoder kPrettyJsonEncoder = const JsonEncoder.withIndent('  ');
+    const JsonEncoder kPrettyJsonEncoder = JsonEncoder.withIndent('  ');
     Cache.instance.setStampFor(kFlutterVersionCheckStampFile, kPrettyJsonEncoder.convert(jsonData));
   }
 

diff --git a/packages/flutter_tools/lib/src/vmservice.dart b/packages/flutter_tools/lib/src/vmservice.dart
index c010e76..fb01e34 100644
--- a/packages/flutter_tools/lib/src/vmservice.dart
+++ b/packages/flutter_tools/lib/src/vmservice.dart

@@ -94,13 +94,13 @@
 }
 
 /// The default VM service request timeout.
-const Duration kDefaultRequestTimeout = const Duration(seconds: 30);
+const Duration kDefaultRequestTimeout = Duration(seconds: 30);
 
 /// Used for RPC requests that may take a long time.
-const Duration kLongRequestTimeout = const Duration(minutes: 1);
+const Duration kLongRequestTimeout = Duration(minutes: 1);
 
 /// Used for RPC requests that should never take a long time.
-const Duration kShortRequestTimeout = const Duration(seconds: 5);
+const Duration kShortRequestTimeout = Duration(seconds: 5);
 
 /// A connection to the Dart VM Service.
 class VMService {