Switch streams to Future<Lists>

packages/flutter_tools/lib/src/commands/emulators.dart

@@ -47,7 +47,7 @@ class EmulatorsCommand extends FlutterCommand {
 
   Future<Null> _launchEmulator(String id) async {
     final List<Emulator> emulators =
-        await emulatorManager.getEmulatorsMatching(id).toList();
+        await emulatorManager.getEmulatorsMatching(id);
 
     if (emulators.isEmpty) {
       printStatus("No emulator found that matches '$id'.");
@@ -62,8 +62,8 @@ class EmulatorsCommand extends FlutterCommand {
   Future<Null> _listEmulators(String searchText) async {
     final List<Emulator> emulators =
         searchText == null
-        ? await emulatorManager.getAllAvailableEmulators().toList()
-        : await emulatorManager.getEmulatorsMatching(searchText).toList();
+        ? await emulatorManager.getAllAvailableEmulators()
+        : await emulatorManager.getEmulatorsMatching(searchText);
 
     if (emulators.isEmpty) {
       printStatus('No emulators available.\n\n'

packages/flutter_tools/lib/src/emulator.dart

@@ -24,8 +24,8 @@ class EmulatorManager {
 
   final List<EmulatorDiscovery> _emulatorDiscoverers = <EmulatorDiscovery>[];
 
-  Stream<Emulator> getEmulatorsMatching(String searchText) async* {
-    final List<Emulator> emulators = await getAllAvailableEmulators().toList();
+  Future<List<Emulator>> getEmulatorsMatching(String searchText) async {
+    final List<Emulator> emulators = await getAllAvailableEmulators();
     searchText = searchText.toLowerCase();
     bool exactlyMatchesEmulatorId(Emulator emulator) =>
         emulator.id?.toLowerCase() == searchText ||
@@ -37,13 +37,11 @@ class EmulatorManager {
     final Emulator exactMatch = emulators.firstWhere(
         exactlyMatchesEmulatorId, orElse: () => null);
     if (exactMatch != null) {
-      yield exactMatch;
-      return;
+      return <Emulator>[exactMatch];
     }
 
     // Match on a id or name starting with [emulatorId].
-    for (Emulator emulator in emulators.where(startsWithEmulatorId))
-      yield emulator;
+    return emulators.where(startsWithEmulatorId).toList();
   }
 
   Iterable<EmulatorDiscovery> get _platformDiscoverers {
@@ -51,12 +49,12 @@ class EmulatorManager {
   }
 
   /// Return the list of all available emulators.
-  Stream<Emulator> getAllAvailableEmulators() async* {
-    for (EmulatorDiscovery discoverer in _platformDiscoverers) {
-      for (Emulator emulator in await discoverer.emulators) {
-        yield emulator;
-      }
-    }
+  Future<List<Emulator>> getAllAvailableEmulators() async {
+    final List<Emulator> emulators = <Emulator>[];
+    Future.forEach(_platformDiscoverers, (EmulatorDiscovery discoverer) async {
+      emulators.addAll(await discoverer.emulators);
+    });
+    return emulators;
   }
 
   /// Whether we're capable of listing any emulators given the current environment configuration.

packages/flutter_tools/test/emulator_test.dart

@@ -14,7 +14,7 @@ void main() {
     testUsingContext('getEmulators', () async {
       // Test that EmulatorManager.getEmulators() doesn't throw.
       final EmulatorManager emulatorManager = new EmulatorManager();
-      final List<Emulator> emulators = await emulatorManager.getAllAvailableEmulators().toList();
+      final List<Emulator> emulators = await emulatorManager.getAllAvailableEmulators();
       expect(emulators, isList);
     });
 
@@ -26,7 +26,7 @@ void main() {
       final EmulatorManager emulatorManager = new TestEmulatorManager(emulators);
 
       Future<Null> expectEmulator(String id, List<Emulator> expected) async {
-        expect(await emulatorManager.getEmulatorsMatching(id).toList(), expected);
+        expect(await emulatorManager.getEmulatorsMatching(id), expected);
       }
       expectEmulator('Nexus_5', <Emulator>[emulator1]);
       expectEmulator('Nexus_5X', <Emulator>[emulator2]);
@@ -44,8 +44,8 @@ class TestEmulatorManager extends EmulatorManager {
   TestEmulatorManager(this.allEmulators);
 
   @override
-  Stream<Emulator> getAllAvailableEmulators() {
-    return new Stream<Emulator>.fromIterable(allEmulators);
+  Future<List<Emulator>> getAllAvailableEmulators() {
+    return new Future<List<Emulator>>.value(allEmulators);
   }
 }