Special-case Timeline.{start,finish}Sync for Fuchsia

sdk/lib/developer/timeline.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.developer;
 
 const bool _isProduct = const bool.fromEnvironment("dart.vm.product");
 
 typedef dynamic TimelineSyncFunction();
 typedef Future TimelineAsyncFunction();
@@ skipping 207 matching lines @@
   final String name;
 
   /// An (optional) set of arguments which will be serialized to JSON and
   /// associated with this block.
   Map _arguments;
   // The start time stamp.
   final int _start;
   // The start time stamp of the thread cpu clock.
   final int _startCpu;
 
-  _SyncBlock._(this.name, this._start, this._startCpu);
+  _SyncBlock._(this.name, this._start, this._startCpu) {
+    _reportBeginEvent(name);
+  }
 
   /// Finish this block of time. At this point, this block can no longer be
   /// used.
   void finish() {
     // Report event to runtime.
     _reportCompleteEvent(
         _start, _startCpu, category, name, _argumentsAsJson(_arguments));
   }
 
   void _appendArguments(Map arguments) {
@@ skipping 33 matching lines @@
 /// Returns the current value from the thread CPU usage clock.
 external int _getThreadCpuClock();
 
 /// Returns the isolate's main port number.
 external int _getIsolateNum();
 
 /// Reports an event for a task.
 external void _reportTaskEvent(int start, int taskId, String phase,
     String category, String name, String argumentsAsJson);
 
+/// Reports a begin event for a synchronous event.
+external void _reportBeginEvent(String name);
+
 /// Reports a complete synchronous event.
 external void _reportCompleteEvent(int start, int startCpu, String category,
     String name, String argumentsAsJson);
 
 /// Reports an instant event.
 external void _reportInstantEvent(
     int start, String category, String name, String argumentsAsJson);