Uncontroversial and backwards compatible 2.0 SDK fixes (#13723)

Small code changes as part of moving the framework SDK forward to a 2.0 dev version.

dev/benchmarks/microbenchmarks/lib/common.dart

@@ -50,11 +50,11 @@ class BenchmarkResultPrinter {
   }
 
   String _printJson() {
-    return JSON.encode(new Map<String, double>.fromIterable(
-      _results,
-      key: (_BenchmarkResult result) => result.name,
-      value: (_BenchmarkResult result) => result.value,
-    ));
+    final Map<String, double> results = <String, double>{};
+    for (_BenchmarkResult result in _results) {
+      results[result.name] = result.value;
+    }
+    return JSON.encode(results);
   }
 
   String _printPlainText() {

dev/bots/test.dart

@@ -373,11 +373,10 @@ Future<Null> _verifyNoBadImports(String workingDirectory) async {
     );
   }
   // Verify that the imports are well-ordered.
-  final Map<String, Set<String>> dependencyMap = new Map<String, Set<String>>.fromIterable(
-    directories,
-    key: (String directory) => directory,
-    value: (String directory) => _findDependencies(path.join(srcPath, directory), errors, checkForMeta: directory != 'foundation'),
-  );
+  final Map<String, Set<String>> dependencyMap = <String, Set<String>>{};
+  for (String directory in directories) {
+    dependencyMap[directory] = _findDependencies(path.join(srcPath, directory), errors, checkForMeta: directory != 'foundation');
+  }
   for (String package in dependencyMap.keys) {
     if (dependencyMap[package].contains(package)) {
       errors.add(

dev/devicelab/lib/tasks/gallery.dart

@@ -53,10 +53,10 @@ class GalleryTransitionTest {
     final Map<String, List<int>> original = JSON.decode(file(
             '${galleryDirectory.path}/build/transition_durations.timeline.json')
         .readAsStringSync());
-    final Map<String, List<int>> transitions = new Map<String, List<int>>.fromIterable(
-        original.keys,
-        key: (String key) => key.replaceAll('/', ''),
-        value: (String key) => original[key]);
+    final Map<String, List<int>> transitions = <String, List<int>>{};
+    for (String key in original.keys) {
+      transitions[key.replaceAll('/', '')] = original[key];
+    }
 
     final Map<String, dynamic> summary = JSON.decode(file('${galleryDirectory.path}/build/transitions.timeline_summary.json').readAsStringSync());
 

dev/devicelab/lib/tasks/perf_tests.dart

@@ -240,11 +240,10 @@ class CompileTest {
     watch.stop();
 
     final RegExp metricExpression = new RegExp(r'([a-zA-Z]+)\(CodeSize\)\: (\d+)');
-    final Map<String, dynamic> metrics = new Map<String, dynamic>.fromIterable(
-      metricExpression.allMatches(compileLog),
-      key: (Match m) => _sdkNameToMetricName(m.group(1)),
-      value: (Match m) => int.parse(m.group(2)),
-    );
+    final Map<String, dynamic> metrics = <String, dynamic>{};
+    for (Match m in metricExpression.allMatches(compileLog)) {
+      metrics[_sdkNameToMetricName(m.group(1))] = int.parse(m.group(2));
+    }
     metrics['aot_snapshot_compile_millis'] = watch.elapsedMilliseconds;
 
     return metrics;

dev/integration_tests/flavors/lib/main.dart

@@ -18,7 +18,7 @@ class _FlavorState extends State<Flavor> {
   @override
   void initState() {
     super.initState();
-    const MethodChannel('flavor').invokeMethod('getFlavor').then((String flavor) {
+    const MethodChannel('flavor').invokeMethod('getFlavor').then((Object flavor) {
       setState(() {
         _flavor = flavor;
       });

dev/tools/gen_date_localizations.dart

@@ -125,7 +125,7 @@ String _jsonToMap(dynamic json) {
   if (json is Iterable)
     return 'const <dynamic>[${json.map(_jsonToMap).join(',')}]';
 
-  if (json is Map) {
+  if (json is Map<String, dynamic>) {
     final StringBuffer buffer = new StringBuffer('const <String, dynamic>{');
     json.forEach((String key, dynamic value) {
       buffer.writeln(_jsonToMapEntry(key, value));

examples/flutter_gallery/lib/gallery/app.dart

@@ -149,17 +149,15 @@ class GalleryAppState extends State<GalleryApp> {
       );
     }
 
-    final Map<String, WidgetBuilder> _kRoutes =
-        new Map<String, WidgetBuilder>.fromIterable(
+    final Map<String, WidgetBuilder> _kRoutes = <String, WidgetBuilder>{};
+    for (GalleryItem item in kAllGalleryItems) {
       // For a different example of how to set up an application routing table
       // using named routes, consider the example in the Navigator class documentation:
       // https://docs.flutter.io/flutter/widgets/Navigator-class.html
-      kAllGalleryItems,
-      key: (GalleryItem item) => item.routeName,
-      value: (GalleryItem item) {
-        return (BuildContext context) => _applyScaleFactor(item.buildRoute(context));
-      },
-    );
+      _kRoutes[item.routeName] = (BuildContext context) {
+        return _applyScaleFactor(item.buildRoute(context));
+      };
+    }
 
     return new MaterialApp(
       title: 'Flutter Gallery',

examples/platform_channel/lib/main.dart

@@ -40,7 +40,7 @@ class _PlatformChannelState extends State<PlatformChannel> {
     eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
   }
 
-  void _onEvent(String event) {
+  void _onEvent(Object event) {
     setState(() {
       _chargingStatus =
           "Battery status: ${event == 'charging' ? '' : 'dis'}charging.";

examples/platform_channel_swift/lib/main.dart

@@ -40,7 +40,7 @@ class _PlatformChannelState extends State<PlatformChannel> {
     eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
   }
 
-  void _onEvent(String event) {
+  void _onEvent(Object event) {
     setState(() {
       _chargingStatus =
           "Battery status: ${event == 'charging' ? '' : 'dis'}charging.";

examples/stocks/lib/stock_strings.dart

@@ -19,7 +19,7 @@ class StockStrings {
 
   static Future<StockStrings> load(Locale locale) {
     return initializeMessages(locale.toString())
-      .then((Null _) {
+      .then((Object _) {
         return new StockStrings(locale);
       });
   }

packages/flutter/lib/src/widgets/binding.dart

@@ -459,7 +459,8 @@ abstract class WidgetsBinding extends BindingBase with SchedulerBinding, Gesture
       observer.didHaveMemoryPressure();
   }
 
-  Future<dynamic> _handleSystemMessage(Map<String, dynamic> message) async {
+  Future<Null> _handleSystemMessage(Object systemMessage) async {
+    final Map<String, dynamic> message = systemMessage;
     final String type = message['type'];
     switch (type) {
       case 'memoryPressure':

packages/flutter/lib/src/widgets/table.dart

@@ -300,11 +300,12 @@ class _TableElement extends RenderObjectElement {
   void update(Table newWidget) {
     assert(!_debugWillReattachChildren);
     assert(() { _debugWillReattachChildren = true; return true; }());
-    final Map<LocalKey, List<Element>> oldKeyedRows = new Map<LocalKey, List<Element>>.fromIterable(
-      _children.where((_TableElementRow row) => row.key != null),
-      key:   (_TableElementRow row) => row.key,
-      value: (_TableElementRow row) => row.children
-    );
+    final Map<LocalKey, List<Element>> oldKeyedRows = <LocalKey, List<Element>>{};
+    for (_TableElementRow row in _children) {
+      if (row.key != null) {
+        oldKeyedRows[row.key] = row.children;
+      }
+    }
     final Iterator<_TableElementRow> oldUnkeyedRows = _children.where((_TableElementRow row) => row.key == null).iterator;
     final List<_TableElementRow> newChildren = <_TableElementRow>[];
     final Set<List<Element>> taken = new Set<List<Element>>();

packages/flutter/test/semantics/semantics_service_test.dart

@@ -12,7 +12,8 @@ void main() {
   test('Semantic announcement', () async {
     final List<Map<String, dynamic>> log = <Map<String, dynamic>>[];
 
-    SystemChannels.accessibility.setMockMessageHandler((Map<String, dynamic> message) async {
+    SystemChannels.accessibility.setMockMessageHandler((Object mockMessage) async {
+      final Map<String, dynamic> message = mockMessage;
       log.add(message);
     });