Add --timing

runtime/vm/timeline.h

 // 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.
 
 #ifndef VM_TIMELINE_H_
 #define VM_TIMELINE_H_
 
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
 
@@ skipping 378 matching lines @@
   intptr_t length_;
   intptr_t block_index_;
 
   // Only accessed under the recorder's lock.
   Isolate* isolate_;
   bool open_;
 
   void Open(Isolate* isolate);
   void Finish();
 
+  friend class Thread;
   friend class ThreadRegistry;
   friend class TimelineEventRecorder;
   friend class TimelineEventRingRecorder;
   friend class TimelineEventEndlessRecorder;
   friend class TimelineTestHelper;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TimelineEventBlock);
 };
 
@@ skipping 182 matching lines @@
   TimelineEventBlock* Next();
 
  private:
   TimelineEventBlock* current_;
   TimelineEventRecorder* recorder_;
 };
 
 }  // namespace dart
 
 #endif  // VM_TIMELINE_H_