Add important Timeline events to whitelist (#12058)

packages/flutter/lib/src/foundation/debug.dart

@@ -28,3 +28,9 @@ bool debugAssertAllFoundationVarsUnset(String reason, { DebugPrintCallback debug
   });
   return true;
 }
+
+/// Arguments to whitelist [Timeline] events in order to be shown in the
+/// developer centric version of the Observatory Timeline.
+const Map<String, String> timelineWhitelistArguments = const <String, String>{
+  'mode': 'basic'
+};

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

@@ -283,7 +283,7 @@ abstract class RendererBinding extends BindingBase with SchedulerBinding, Servic
   @override
   Future<Null> performReassemble() async {
     await super.performReassemble();
-    Timeline.startSync('Dirty Render Tree');
+    Timeline.startSync('Dirty Render Tree', arguments: timelineWhitelistArguments);
     try {
       renderView.reassemble();
     } finally {

packages/flutter/lib/src/rendering/object.dart

@@ -126,7 +126,7 @@ class PaintingContext {
   void paintChild(RenderObject child, Offset offset) {
     assert(() {
       if (debugProfilePaintsEnabled)
-        Timeline.startSync('${child.runtimeType}');
+        Timeline.startSync('${child.runtimeType}', arguments: timelineWhitelistArguments);
       return true;
     });
 
@@ -1075,7 +1075,7 @@ class PipelineOwner {
   ///
   /// See [RendererBinding] for an example of how this function is used.
   void flushLayout() {
-    Timeline.startSync('Layout');
+    Timeline.startSync('Layout', arguments: timelineWhitelistArguments);
     _debugDoingLayout = true;
     try {
       // TODO(ianh): assert that we're not allowing previously dirty nodes to redirty themeselves
@@ -1146,7 +1146,7 @@ class PipelineOwner {
   ///
   /// See [RendererBinding] for an example of how this function is used.
   void flushPaint() {
-    Timeline.startSync('Paint');
+    Timeline.startSync('Paint', arguments: timelineWhitelistArguments);
     _debugDoingPaint = true;
     try {
       final List<RenderObject> dirtyNodes = _nodesNeedingPaint;

packages/flutter/lib/src/rendering/view.dart

@@ -184,7 +184,7 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
   ///
   /// Actually causes the output of the rendering pipeline to appear on screen.
   void compositeFrame() {
-    Timeline.startSync('Compositing');
+    Timeline.startSync('Compositing', arguments: timelineWhitelistArguments);
     try {
       final ui.SceneBuilder builder = new ui.SceneBuilder();
       layer.addToScene(builder, Offset.zero);

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

@@ -585,7 +585,7 @@ abstract class SchedulerBinding extends BindingBase {
   /// statements printed during a frame from those printed between frames (e.g.
   /// in response to events or timers).
   void handleBeginFrame(Duration rawTimeStamp) {
-    Timeline.startSync('Frame');
+    Timeline.startSync('Frame', arguments: timelineWhitelistArguments);
     _firstRawTimeStampInEpoch ??= rawTimeStamp;
     _currentFrameTimeStamp = _adjustForEpoch(rawTimeStamp ?? _lastRawTimeStamp);
     if (rawTimeStamp != null)
@@ -616,7 +616,7 @@ abstract class SchedulerBinding extends BindingBase {
     _hasScheduledFrame = false;
     try {
       // TRANSIENT FRAME CALLBACKS
-      Timeline.startSync('Animate');
+      Timeline.startSync('Animate', arguments: timelineWhitelistArguments);
       _schedulerPhase = SchedulerPhase.transientCallbacks;
       final Map<int, _FrameCallbackEntry> callbacks = _transientCallbacks;
       _transientCallbacks = <int, _FrameCallbackEntry>{};

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

@@ -2224,7 +2224,7 @@ class BuildOwner {
       _debugBuilding = true;
       return true;
     });
-    Timeline.startSync('Build');
+    Timeline.startSync('Build', arguments: timelineWhitelistArguments);
     try {
       _scheduledFlushDirtyElements = true;
       if (callback != null) {
@@ -2341,7 +2341,7 @@ class BuildOwner {
   /// After the current call stack unwinds, a microtask that notifies listeners
   /// about changes to global keys will run.
   void finalizeTree() {
-    Timeline.startSync('Finalize tree');
+    Timeline.startSync('Finalize tree', arguments: timelineWhitelistArguments);
     try {
       lockState(() {
         _inactiveElements._unmountAll(); // this unregisters the GlobalKeys