Use Dart 2 camel case constants (#15360)

diff --git a/packages/flutter_tools/test/asset_bundle_package_fonts_test.dart b/packages/flutter_tools/test/asset_bundle_package_fonts_test.dart
index 8c720b5..db8270f 100644
--- a/packages/flutter_tools/test/asset_bundle_package_fonts_test.dart
+++ b/packages/flutter_tools/test/asset_bundle_package_fonts_test.dart
@@ -65,7 +65,7 @@
         final String entryKey = 'packages/$packageName/$packageFont';
         expect(bundle.entries.containsKey(entryKey), true);
         expect(
-          UTF8.decode(await bundle.entries[entryKey].contentsAsBytes()),
+          utf8.decode(await bundle.entries[entryKey].contentsAsBytes()),
           packageFont,
         );
       }
@@ -73,14 +73,14 @@
       for (String localFont in localFonts) {
         expect(bundle.entries.containsKey(localFont), true);
         expect(
-          UTF8.decode(await bundle.entries[localFont].contentsAsBytes()),
+          utf8.decode(await bundle.entries[localFont].contentsAsBytes()),
           localFont,
         );
       }
     }
 
     expect(
-      UTF8.decode(await bundle.entries['FontManifest.json'].contentsAsBytes()),
+      utf8.decode(await bundle.entries['FontManifest.json'].contentsAsBytes()),
       expectedAssetManifest,
     );
   }
diff --git a/packages/flutter_tools/test/asset_bundle_package_test.dart b/packages/flutter_tools/test/asset_bundle_package_test.dart
index af1183c..630a32b 100644
--- a/packages/flutter_tools/test/asset_bundle_package_test.dart
+++ b/packages/flutter_tools/test/asset_bundle_package_test.dart
@@ -72,14 +72,14 @@
         final String entryKey = 'packages/$packageName/$asset';
         expect(bundle.entries.containsKey(entryKey), true);
         expect(
-          UTF8.decode(await bundle.entries[entryKey].contentsAsBytes()),
+          utf8.decode(await bundle.entries[entryKey].contentsAsBytes()),
           asset,
         );
       }
     }
 
     expect(
-      UTF8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+      utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
       expectedAssetManifest,
     );
   }
@@ -127,7 +127,7 @@
       expect(bundle.entries.length, 2); // LICENSE, AssetManifest
       const String expectedAssetManifest = '{}';
       expect(
-        UTF8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+        utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
         expectedAssetManifest,
       );
     });
@@ -147,7 +147,7 @@
       expect(bundle.entries.length, 2); // LICENSE, AssetManifest
       const String expectedAssetManifest = '{}';
       expect(
-        UTF8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+        utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
         expectedAssetManifest,
       );
 
diff --git a/packages/flutter_tools/test/asset_bundle_test.dart b/packages/flutter_tools/test/asset_bundle_test.dart
index 1f9f053..c8f663c 100644
--- a/packages/flutter_tools/test/asset_bundle_test.dart
+++ b/packages/flutter_tools/test/asset_bundle_test.dart
@@ -59,7 +59,7 @@
       expect(bundle.entries.length, 1);
       const String expectedAssetManifest = '{}';
       expect(
-        UTF8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
+        utf8.decode(await bundle.entries['AssetManifest.json'].contentsAsBytes()),
         expectedAssetManifest,
       );
     });
diff --git a/packages/flutter_tools/test/asset_bundle_variant_test.dart b/packages/flutter_tools/test/asset_bundle_variant_test.dart
index 207e445..d3c37f4 100644
--- a/packages/flutter_tools/test/asset_bundle_variant_test.dart
+++ b/packages/flutter_tools/test/asset_bundle_variant_test.dart
@@ -77,7 +77,7 @@
       // The main asset file, /a/b/c/foo, and its variants exist.
       for (String asset in assets) {
         expect(bundle.entries.containsKey(asset), true);
-        expect(UTF8.decode(await bundle.entries[asset].contentsAsBytes()), asset);
+        expect(utf8.decode(await bundle.entries[asset].contentsAsBytes()), asset);
       }
 
       fs.file('a/b/c/foo').deleteSync();
@@ -89,7 +89,7 @@
       expect(bundle.entries.containsKey('a/b/c/foo'), false);
       for (String asset in assets.skip(1)) {
         expect(bundle.entries.containsKey(asset), true);
-        expect(UTF8.decode(await bundle.entries[asset].contentsAsBytes()), asset);
+        expect(utf8.decode(await bundle.entries[asset].contentsAsBytes()), asset);
       }
     });
 
diff --git a/packages/flutter_tools/test/base/build_test.dart b/packages/flutter_tools/test/base/build_test.dart
index 53786ef..1c14819 100644
--- a/packages/flutter_tools/test/base/build_test.dart
+++ b/packages/flutter_tools/test/base/build_test.dart
@@ -4,7 +4,7 @@
 
 import 'dart:async';
 import 'dart:convert';
-import 'dart:convert' show JSON;
+import 'dart:convert' show json;
 
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/artifacts.dart';
@@ -95,26 +95,26 @@
         await fs.file('b.dart').writeAsString('This is b');
         final Fingerprint fingerprint = new Fingerprint.fromBuildInputs(<String, String>{}, <String>['a.dart', 'b.dart']);
 
-        final Map<String, dynamic> json = JSON.decode(fingerprint.toJson());
-        expect(json['files'], hasLength(2));
-        expect(json['files']['a.dart'], '8a21a15fad560b799f6731d436c1b698');
-        expect(json['files']['b.dart'], '6f144e08b58cd0925328610fad7ac07c');
+        final Map<String, dynamic> jsonObject = json.decode(fingerprint.toJson());
+        expect(jsonObject['files'], hasLength(2));
+        expect(jsonObject['files']['a.dart'], '8a21a15fad560b799f6731d436c1b698');
+        expect(jsonObject['files']['b.dart'], '6f144e08b58cd0925328610fad7ac07c');
       }, overrides: <Type, Generator>{ FileSystem: () => fs });
 
       testUsingContext('includes framework version', () {
         final Fingerprint fingerprint = new Fingerprint.fromBuildInputs(<String, String>{}, <String>[]);
 
-        final Map<String, dynamic> json = JSON.decode(fingerprint.toJson());
-        expect(json['version'], mockVersion.frameworkRevision);
+        final Map<String, dynamic> jsonObject = json.decode(fingerprint.toJson());
+        expect(jsonObject['version'], mockVersion.frameworkRevision);
       }, overrides: <Type, Generator>{ FlutterVersion: () => mockVersion });
 
       testUsingContext('includes provided properties', () {
         final Fingerprint fingerprint = new Fingerprint.fromBuildInputs(<String, String>{'a': 'A', 'b': 'B'}, <String>[]);
 
-        final Map<String, dynamic> json = JSON.decode(fingerprint.toJson());
-        expect(json['properties'], hasLength(2));
-        expect(json['properties']['a'], 'A');
-        expect(json['properties']['b'], 'B');
+        final Map<String, dynamic> jsonObject = json.decode(fingerprint.toJson());
+        expect(jsonObject['properties'], hasLength(2));
+        expect(jsonObject['properties']['a'], 'A');
+        expect(jsonObject['properties']['b'], 'B');
       }, overrides: <Type, Generator>{ FlutterVersion: () => mockVersion });
     });
 
@@ -126,7 +126,7 @@
       });
 
       testUsingContext('creates fingerprint from valid JSON', () async {
-        final String json = JSON.encode(<String, dynamic>{
+        final String jsonString = json.encode(<String, dynamic>{
           'version': kVersion,
           'properties': <String, String>{
             'buildMode': BuildMode.release.toString(),
@@ -138,8 +138,8 @@
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
           },
         });
-        final Fingerprint fingerprint = new Fingerprint.fromJson(json);
-        final Map<String, dynamic> content = JSON.decode(fingerprint.toJson());
+        final Fingerprint fingerprint = new Fingerprint.fromJson(jsonString);
+        final Map<String, dynamic> content = json.decode(fingerprint.toJson());
         expect(content, hasLength(3));
         expect(content['version'], mockVersion.frameworkRevision);
         expect(content['properties'], hasLength(3));
@@ -154,31 +154,31 @@
       });
 
       testUsingContext('throws ArgumentError for unknown versions', () async {
-        final String json = JSON.encode(<String, dynamic>{
+        final String jsonString = json.encode(<String, dynamic>{
           'version': 'bad',
           'properties':<String, String>{},
           'files':<String, String>{},
         });
-        expect(() => new Fingerprint.fromJson(json), throwsArgumentError);
+        expect(() => new Fingerprint.fromJson(jsonString), throwsArgumentError);
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
 
       testUsingContext('throws ArgumentError if version is not present', () async {
-        final String json = JSON.encode(<String, dynamic>{
+        final String jsonString = json.encode(<String, dynamic>{
           'properties':<String, String>{},
           'files':<String, String>{},
         });
-        expect(() => new Fingerprint.fromJson(json), throwsArgumentError);
+        expect(() => new Fingerprint.fromJson(jsonString), throwsArgumentError);
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
 
       testUsingContext('treats missing properties and files entries as if empty', () async {
-        final String json = JSON.encode(<String, dynamic>{
+        final String jsonString = json.encode(<String, dynamic>{
           'version': kVersion,
         });
-        expect(new Fingerprint.fromJson(json), new Fingerprint.fromBuildInputs(<String, String>{}, <String>[]));
+        expect(new Fingerprint.fromJson(jsonString), new Fingerprint.fromBuildInputs(<String, String>{}, <String>[]));
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
@@ -197,7 +197,7 @@
         b['properties'] = <String, String>{
           'buildMode': BuildMode.release.toString(),
         };
-        expect(new Fingerprint.fromJson(JSON.encode(a)) == new Fingerprint.fromJson(JSON.encode(b)), isFalse);
+        expect(new Fingerprint.fromJson(json.encode(a)) == new Fingerprint.fromJson(json.encode(b)), isFalse);
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
@@ -216,7 +216,7 @@
           'a.dart': '8a21a15fad560b799f6731d436c1b698',
           'b.dart': '6f144e08b58cd0925328610fad7ac07d',
         };
-        expect(new Fingerprint.fromJson(JSON.encode(a)) == new Fingerprint.fromJson(JSON.encode(b)), isFalse);
+        expect(new Fingerprint.fromJson(json.encode(a)) == new Fingerprint.fromJson(json.encode(b)), isFalse);
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
@@ -235,7 +235,7 @@
           'a.dart': '8a21a15fad560b799f6731d436c1b698',
           'c.dart': '6f144e08b58cd0925328610fad7ac07d',
         };
-        expect(new Fingerprint.fromJson(JSON.encode(a)) == new Fingerprint.fromJson(JSON.encode(b)), isFalse);
+        expect(new Fingerprint.fromJson(json.encode(a)) == new Fingerprint.fromJson(json.encode(b)), isFalse);
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
@@ -253,7 +253,7 @@
             'b.dart': '6f144e08b58cd0925328610fad7ac07c',
           },
         };
-        expect(new Fingerprint.fromJson(JSON.encode(a)) == new Fingerprint.fromJson(JSON.encode(a)), isTrue);
+        expect(new Fingerprint.fromJson(json.encode(a)) == new Fingerprint.fromJson(json.encode(a)), isTrue);
       }, overrides: <Type, Generator>{
         FlutterVersion: () => mockVersion,
       });
@@ -344,7 +344,7 @@
     };
 
     Future<Null> writeFingerprint({ Map<String, String> files = const <String, String>{} }) {
-      return fs.file('output.snapshot.d.fingerprint').writeAsString(JSON.encode(<String, dynamic>{
+      return fs.file('output.snapshot.d.fingerprint').writeAsString(json.encode(<String, dynamic>{
         'version': kVersion,
         'properties': <String, String>{
           'buildMode': BuildMode.debug.toString(),
@@ -371,14 +371,14 @@
       String entryPoint: 'main.dart',
       Map<String, String> checksums = const <String, String>{},
     }) {
-      final Map<String, dynamic> json = JSON.decode(fs.file('output.snapshot.d.fingerprint').readAsStringSync());
-      expect(json['properties']['entryPoint'], entryPoint);
-      expect(json['files'], hasLength(checksums.length + 2));
+      final Map<String, dynamic> jsonObject = json.decode(fs.file('output.snapshot.d.fingerprint').readAsStringSync());
+      expect(jsonObject['properties']['entryPoint'], entryPoint);
+      expect(jsonObject['files'], hasLength(checksums.length + 2));
       checksums.forEach((String path, String checksum) {
-        expect(json['files'][path], checksum);
+        expect(jsonObject['files'][path], checksum);
       });
-      expect(json['files'][kVmSnapshotData], '2ec34912477a46c03ddef07e8b909b46');
-      expect(json['files'][kIsolateSnapshotData], '621b3844bb7d4d17d2cfc5edf9a91c4c');
+      expect(jsonObject['files'][kVmSnapshotData], '2ec34912477a46c03ddef07e8b909b46');
+      expect(jsonObject['files'][kIsolateSnapshotData], '621b3844bb7d4d17d2cfc5edf9a91c4c');
     }
 
     testUsingContext('builds snapshot and fingerprint when no fingerprint is present', () async {
diff --git a/packages/flutter_tools/test/commands/config_test.dart b/packages/flutter_tools/test/commands/config_test.dart
index c096e3e..9485201 100644
--- a/packages/flutter_tools/test/commands/config_test.dart
+++ b/packages/flutter_tools/test/commands/config_test.dart
@@ -30,14 +30,14 @@
       await command.handleMachine();
 
       expect(logger.statusText, isNotEmpty);
-      final dynamic json = JSON.decode(logger.statusText);
-      expect(json, isMap);
+      final dynamic jsonObject = json.decode(logger.statusText);
+      expect(jsonObject, isMap);
 
-      expect(json.containsKey('android-studio-dir'), true);
-      expect(json['android-studio-dir'], isNotNull);
+      expect(jsonObject.containsKey('android-studio-dir'), true);
+      expect(jsonObject['android-studio-dir'], isNotNull);
 
-      expect(json.containsKey('android-sdk'), true);
-      expect(json['android-sdk'], isNotNull);
+      expect(jsonObject.containsKey('android-sdk'), true);
+      expect(jsonObject['android-sdk'], isNotNull);
     }, overrides: <Type, Generator>{
       AndroidStudio: () => mockAndroidStudio,
       AndroidSdk: () => mockAndroidSdk,
diff --git a/packages/flutter_tools/test/commands/create_test.dart b/packages/flutter_tools/test/commands/create_test.dart
index a21ec7b..5c1e2d4 100644
--- a/packages/flutter_tools/test/commands/create_test.dart
+++ b/packages/flutter_tools/test/commands/create_test.dart
@@ -207,7 +207,7 @@
             <String>[file.path],
             workingDirectory: projectDir.path,
           );
-          final String formatted = await process.stdout.transform(UTF8.decoder).join();
+          final String formatted = await process.stdout.transform(utf8.decoder).join();
 
           expect(original, formatted, reason: file.path);
         }
diff --git a/packages/flutter_tools/test/compile_test.dart b/packages/flutter_tools/test/compile_test.dart
index 36f3847..45e0bb9 100644
--- a/packages/flutter_tools/test/compile_test.dart
+++ b/packages/flutter_tools/test/compile_test.dart
@@ -41,7 +41,7 @@
       final BufferLogger logger = context[Logger];
       when(mockFrontendServer.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'result abc\nline1\nline2\nabc /path/to/main.dart.dill'
             ))
           ));
@@ -60,7 +60,7 @@
 
       when(mockFrontendServer.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'result abc\nline1\nline2\nabc'
             ))
           ));
@@ -82,7 +82,7 @@
 
       when(mockFrontendServer.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-          new Future<List<int>>.value(UTF8.encode(
+          new Future<List<int>>.value(utf8.encode(
               'result abc\nline1\nline2\nabc'
           ))
       ));
@@ -134,7 +134,7 @@
 
       when(mockFrontendServer.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'result abc\nline1\nline2\nabc /path/to/main.dart.dill'
             ))
           ));
@@ -169,7 +169,7 @@
       final StreamController<List<int>> streamController = new StreamController<List<int>>();
       when(mockFrontendServer.stdout)
           .thenAnswer((Invocation invocation) => streamController.stream);
-      streamController.add(UTF8.encode('result abc\nline0\nline1\nabc /path/to/main.dart.dill\n'));
+      streamController.add(utf8.encode('result abc\nline0\nline1\nabc /path/to/main.dart.dill\n'));
       await generator.recompile('/path/to/main.dart', null /* invalidatedFiles */);
       expect(mockFrontendServerStdIn.getAndClear(), 'compile /path/to/main.dart\n');
 
@@ -192,7 +192,7 @@
       final StreamController<List<int>> streamController = new StreamController<List<int>>();
       when(mockFrontendServer.stdout)
           .thenAnswer((Invocation invocation) => streamController.stream);
-      streamController.add(UTF8.encode(
+      streamController.add(utf8.encode(
         'result abc\nline0\nline1\nabc /path/to/main.dart.dill\n'
       ));
       await generator.recompile('/path/to/main.dart', null /* invalidatedFiles */);
@@ -222,7 +222,7 @@
   // Put content into the output stream after generator.recompile gets
   // going few lines below, resets completer.
   new Future<List<int>>(() {
-    streamController.add(UTF8.encode(mockCompilerOutput));
+    streamController.add(utf8.encode(mockCompilerOutput));
   });
   final String output = await generator.recompile(null /* mainPath */, <String>['/path/to/main.dart']);
   expect(output, equals('/path/to/main.dart.dill'));
diff --git a/packages/flutter_tools/test/crash_reporting_test.dart b/packages/flutter_tools/test/crash_reporting_test.dart
index 2416d25..de3b23d 100644
--- a/packages/flutter_tools/test/crash_reporting_test.dart
+++ b/packages/flutter_tools/test/crash_reporting_test.dart
@@ -53,7 +53,7 @@
         String boundary = request.headers['Content-Type'];
         boundary = boundary.substring(boundary.indexOf('boundary=') + 9);
         fields = new Map<String, String>.fromIterable(
-          UTF8.decode(request.bodyBytes)
+          utf8.decode(request.bodyBytes)
               .split('--$boundary')
               .map<List<String>>((String part) {
                 final Match nameMatch = new RegExp(r'name="(.*)"').firstMatch(part);
diff --git a/packages/flutter_tools/test/devfs_test.dart b/packages/flutter_tools/test/devfs_test.dart
index 6252f45..01eba00 100644
--- a/packages/flutter_tools/test/devfs_test.dart
+++ b/packages/flutter_tools/test/devfs_test.dart
@@ -49,17 +49,17 @@
     test('string', () {
       final DevFSStringContent content = new DevFSStringContent('some string');
       expect(content.string, 'some string');
-      expect(content.bytes, orderedEquals(UTF8.encode('some string')));
+      expect(content.bytes, orderedEquals(utf8.encode('some string')));
       expect(content.isModified, isTrue);
       expect(content.isModified, isFalse);
       content.string = 'another string';
       expect(content.string, 'another string');
-      expect(content.bytes, orderedEquals(UTF8.encode('another string')));
+      expect(content.bytes, orderedEquals(utf8.encode('another string')));
       expect(content.isModified, isTrue);
       expect(content.isModified, isFalse);
-      content.bytes = UTF8.encode('foo bar');
+      content.bytes = utf8.encode('foo bar');
       expect(content.string, 'foo bar');
-      expect(content.bytes, orderedEquals(UTF8.encode('foo bar')));
+      expect(content.bytes, orderedEquals(utf8.encode('foo bar')));
       expect(content.isModified, isTrue);
       expect(content.isModified, isFalse);
     });
@@ -97,7 +97,7 @@
       ]);
       expect(devFS.assetPathsToEvict, isEmpty);
 
-      final List<String> packageSpecOnDevice = LineSplitter.split(UTF8.decode(
+      final List<String> packageSpecOnDevice = LineSplitter.split(utf8.decode(
           await devFSOperations.devicePathToContent[fs.path.toUri('.packages')].contentsAsBytes()
       )).toList();
       expect(packageSpecOnDevice,
@@ -397,7 +397,7 @@
     }
     _server.listen((HttpRequest request) {
       final String fsName = request.headers.value('dev_fs_name');
-      final String devicePath = UTF8.decode(BASE64.decode(request.headers.value('dev_fs_uri_b64')));
+      final String devicePath = utf8.decode(base64.decode(request.headers.value('dev_fs_uri_b64')));
       messages.add('writeFile $fsName $devicePath');
       request.drain<List<int>>().then<Null>((List<int> value) {
         request.response
diff --git a/packages/flutter_tools/test/ios/code_signing_test.dart b/packages/flutter_tools/test/ios/code_signing_test.dart
index 82e04a9..015eb1d 100644
--- a/packages/flutter_tools/test/ios/code_signing_test.dart
+++ b/packages/flutter_tools/test/ios/code_signing_test.dart
@@ -125,7 +125,7 @@
       when(mockProcess.stdin).thenReturn(mockStdIn);
       when(mockProcess.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'subject= /CN=iPhone Developer: Profile 1 (1111AAAA11)/OU=3333CCCC33/O=My Team/C=US'
             ))
           ));
@@ -184,7 +184,7 @@
       when(mockOpenSslProcess.stdin).thenReturn(mockOpenSslStdIn);
       when(mockOpenSslProcess.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'subject= /CN=iPhone Developer: Profile 3 (3333CCCC33)/OU=4444DDDD44/O=My Team/C=US'
             ))
           ));
@@ -254,7 +254,7 @@
       when(mockOpenSslProcess.stdin).thenReturn(mockOpenSslStdIn);
       when(mockOpenSslProcess.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'subject= /CN=iPhone Developer: Profile 1 (1111AAAA11)/OU=5555EEEE55/O=My Team/C=US'
             )),
           ));
@@ -316,7 +316,7 @@
       when(mockOpenSslProcess.stdin).thenReturn(mockOpenSslStdIn);
       when(mockOpenSslProcess.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'subject= /CN=iPhone Developer: Profile 3 (3333CCCC33)/OU=4444DDDD44/O=My Team/C=US'
             ))
           ));
@@ -385,7 +385,7 @@
       when(mockOpenSslProcess.stdin).thenReturn(mockOpenSslStdIn);
       when(mockOpenSslProcess.stdout)
           .thenAnswer((Invocation invocation) => new Stream<List<int>>.fromFuture(
-            new Future<List<int>>.value(UTF8.encode(
+            new Future<List<int>>.value(utf8.encode(
               'subject= /CN=iPhone Developer: Profile 3 (3333CCCC33)/OU=4444DDDD44/O=My Team/C=US'
             ))
           ));
diff --git a/packages/flutter_tools/test/ios/devices_test.dart b/packages/flutter_tools/test/ios/devices_test.dart
index 60e9914..099e7afd 100644
--- a/packages/flutter_tools/test/ios/devices_test.dart
+++ b/packages/flutter_tools/test/ios/devices_test.dart
@@ -107,7 +107,7 @@
             .thenAnswer((Invocation invocation) => const Stream<List<int>>.empty());
         // Delay return of exitCode until after stdout stream data, since it terminates the logger.
         when(mockProcess.exitCode)
-            .thenAnswer((Invocation invocation) => new Future<int>.delayed(Duration.ZERO, () => 0));
+            .thenAnswer((Invocation invocation) => new Future<int>.delayed(Duration.zero, () => 0));
         return new Future<Process>.value(mockProcess);
       });
 
diff --git a/packages/flutter_tools/test/ios/simulators_test.dart b/packages/flutter_tools/test/ios/simulators_test.dart
index 9ef1cf4..d717f96 100644
--- a/packages/flutter_tools/test/ios/simulators_test.dart
+++ b/packages/flutter_tools/test/ios/simulators_test.dart
@@ -289,7 +289,7 @@
             .thenAnswer((Invocation invocation) => const Stream<List<int>>.empty());
         // Delay return of exitCode until after stdout stream data, since it terminates the logger.
         when(mockProcess.exitCode)
-            .thenAnswer((Invocation invocation) => new Future<int>.delayed(Duration.ZERO, () => 0));
+            .thenAnswer((Invocation invocation) => new Future<int>.delayed(Duration.zero, () => 0));
         return new Future<Process>.value(mockProcess);
       })
           .thenThrow(new TestFailure('Should start one process only'));
diff --git a/packages/flutter_tools/test/src/mocks.dart b/packages/flutter_tools/test/src/mocks.dart
index 6c29a5e..d7e4a1c 100644
--- a/packages/flutter_tools/test/src/mocks.dart
+++ b/packages/flutter_tools/test/src/mocks.dart
@@ -169,13 +169,13 @@
 /// some lines to stdout before it exits.
 class PromptingProcess implements Process {
   Future<Null> showPrompt(String prompt, List<String> outputLines) async {
-    _stdoutController.add(UTF8.encode(prompt));
+    _stdoutController.add(utf8.encode(prompt));
     final List<int> bytesOnStdin = await _stdin.future;
     // Echo stdin to stdout.
     _stdoutController.add(bytesOnStdin);
-    if (bytesOnStdin[0] == UTF8.encode('y')[0]) {
+    if (bytesOnStdin[0] == utf8.encode('y')[0]) {
       for (final String line in outputLines)
-        _stdoutController.add(UTF8.encode('$line\n'));
+        _stdoutController.add(utf8.encode('$line\n'));
     }
     await _stdoutController.close();
   }
@@ -219,7 +219,7 @@
 /// An IOSink that collects whatever is written to it.
 class MemoryIOSink implements IOSink {
   @override
-  Encoding encoding = UTF8;
+  Encoding encoding = utf8;
 
   final List<List<int>> writes = <List<int>>[];
 
@@ -291,7 +291,7 @@
   Stream<List<int>> get stdin => _stdin.stream;
 
   void simulateStdin(String line) {
-    _stdin.add(UTF8.encode('$line\n'));
+    _stdin.add(utf8.encode('$line\n'));
   }
 
   List<String> get writtenToStdout => _stdout.writes.map(_stdout.encoding.decode).toList();
diff --git a/packages/flutter_tools/test/version_test.dart b/packages/flutter_tools/test/version_test.dart
index 331151d..4e53722 100644
--- a/packages/flutter_tools/test/version_test.dart
+++ b/packages/flutter_tools/test/version_test.dart
@@ -30,7 +30,7 @@
 
     setUpAll(() {
       Cache.disableLocking();
-      FlutterVersion.kPauseToLetUserReadTheMessage = Duration.ZERO;
+      FlutterVersion.kPauseToLetUserReadTheMessage = Duration.zero;
     });
 
     setUp(() {
@@ -300,7 +300,7 @@
       return stampJson;
 
     if (stamp != null)
-      return JSON.encode(stamp.toJson());
+      return json.encode(stamp.toJson());
 
     return null;
   });
@@ -309,7 +309,7 @@
     expect(invocation.positionalArguments.first, VersionCheckStamp.kFlutterVersionCheckStampFile);
 
     if (expectSetStamp) {
-      stamp = VersionCheckStamp.fromJson(JSON.decode(invocation.positionalArguments[1]));
+      stamp = VersionCheckStamp.fromJson(json.decode(invocation.positionalArguments[1]));
       return null;
     }