rename TracingCategory to TimelineStream (#3822)

examples/flutter_gallery/test_driver/transitions_perf_test.dart

@@ -80,10 +80,10 @@ void main() {
           }
         }
       },
-      categories: const <TracingCategory>[
-        TracingCategory.dart,
-        TracingCategory.gc,
-        TracingCategory.compiler
+      streams: const <TimelineStream>[
+        TimelineStream.dart,
+        TimelineStream.gc,
+        TimelineStream.compiler
       ]);
       new TimelineSummary.summarize(timeline)
         ..writeSummaryToFile('transitions_perf', pretty: true)

packages/flutter_driver/lib/flutter_driver.dart

@@ -16,7 +16,7 @@ export 'src/driver.dart' show
   CommonFinders,
   EvaluatorFunction,
   FlutterDriver,
-  TracingCategory;
+  TimelineStream;
 
 export 'src/error.dart' show
   DriverError,

packages/flutter_driver/lib/src/driver.dart

@@ -15,27 +15,27 @@ import 'health.dart';
 import 'message.dart';
 import 'timeline.dart';
 
-enum TracingCategory {
+enum TimelineStream {
   all, api, compiler, dart, debugger, embedder, gc, isolate, vm
 }
 
-const List<TracingCategory> _defaultCategories = const <TracingCategory>[TracingCategory.all];
+const List<TimelineStream> _defaultStreams = const <TimelineStream>[TimelineStream.all];
 
 // See https://github.com/dart-lang/sdk/blob/master/runtime/vm/timeline.cc#L32
-String _tracingCategoriesToString(List<TracingCategory> categories) {
-  final String contents = categories.map((TracingCategory category) {
-    switch(category) {
-      case TracingCategory.all: return 'all';
-      case TracingCategory.api: return 'API';
-      case TracingCategory.compiler: return 'Compiler';
-      case TracingCategory.dart: return 'Dart';
-      case TracingCategory.debugger: return 'Debugger';
-      case TracingCategory.embedder: return 'Embedder';
-      case TracingCategory.gc: return 'GC';
-      case TracingCategory.isolate: return 'Isolate';
-      case TracingCategory.vm: return 'VM';
+String _timelineStreamsToString(List<TimelineStream> streams) {
+  final String contents = streams.map((TimelineStream stream) {
+    switch(stream) {
+      case TimelineStream.all: return 'all';
+      case TimelineStream.api: return 'API';
+      case TimelineStream.compiler: return 'Compiler';
+      case TimelineStream.dart: return 'Dart';
+      case TimelineStream.debugger: return 'Debugger';
+      case TimelineStream.embedder: return 'Embedder';
+      case TimelineStream.gc: return 'GC';
+      case TimelineStream.isolate: return 'Isolate';
+      case TimelineStream.vm: return 'VM';
       default:
-        throw 'Unknown tracing category $category';
+        throw 'Unknown timeline stream $stream';
     }
   }).join(', ');
   return '[$contents]';
@@ -249,11 +249,11 @@ class FlutterDriver {
   }
 
   /// Starts recording performance traces.
-  Future<Null> startTracing({List<TracingCategory> categories: _defaultCategories}) async {
-    assert(categories != null && categories.length > 0);
+  Future<Null> startTracing({List<TimelineStream> streams: _defaultStreams}) async {
+    assert(streams != null && streams.length > 0);
     try {
       await _peer.sendRequest(_kSetVMTimelineFlagsMethod, <String, String>{
-        'recordedStreams': _tracingCategoriesToString(categories)
+        'recordedStreams': _timelineStreamsToString(streams)
       });
       return null;
     } catch(error, stackTrace) {
@@ -286,8 +286,8 @@ class FlutterDriver {
   ///
   /// This is merely a convenience wrapper on top of [startTracing] and
   /// [stopTracingAndDownloadTimeline].
-  Future<Timeline> traceAction(Future<dynamic> action(), { List<TracingCategory> categories: _defaultCategories }) async {
-    await startTracing(categories: categories);
+  Future<Timeline> traceAction(Future<dynamic> action(), { List<TimelineStream> streams: _defaultStreams }) async {
+    await startTracing(streams: streams);
     await action();
     return stopTracingAndDownloadTimeline();
   }

packages/flutter_driver/test/flutter_driver_test.dart

@@ -236,8 +236,8 @@ void main() {
       });
     });
 
-    group('traceAction categories', () {
-      test('specify non-default categories', () async {
+    group('traceAction with timeline streams', () {
+      test('specify non-default timeline streams', () async {
         bool actionCalled = false;
         bool startTracingCalled = false;
         bool stopTracingCalled = false;
@@ -267,10 +267,10 @@ void main() {
         Timeline timeline = await driver.traceAction(() {
           actionCalled = true;
         },
-        categories: const <TracingCategory>[
-          TracingCategory.dart,
-          TracingCategory.gc,
-          TracingCategory.compiler
+        streams: const <TimelineStream>[
+          TimelineStream.dart,
+          TimelineStream.gc,
+          TimelineStream.compiler
         ]);
 
         expect(actionCalled, isTrue);