Introduce a way to grab heap stats.

include/v8-profiler.h

Index: include/v8-profiler.h
diff --git a/include/v8-profiler.h b/include/v8-profiler.h
index e36659fb48da438082baa47090c66ab77ca05da5..7cc3e1968742bc7924a04798bd95feebe737af28 100644
--- a/include/v8-profiler.h
+++ b/include/v8-profiler.h
@@ -417,6 +417,10 @@ class V8EXPORT HeapProfiler {
       HeapSnapshot::Type type = HeapSnapshot::kFull,
       ActivityControl* control = NULL);
 
+  static void StartHeapObjectsTracking();
+  static void StopHeapObjectsTracking();
+  static void PushHeapObjectsStats(OutputStream* stream);
+
   /**
    * Deletes all snapshots taken. All previously returned pointers to
    * snapshots and their contents become invalid after this call.