Added --trace_idle_notification_verbose which prints out the idle notificatino heap state.

src/heap/gc-idle-time-handler.h

Index: src/heap/gc-idle-time-handler.h
diff --git a/src/heap/gc-idle-time-handler.h b/src/heap/gc-idle-time-handler.h
index cae6936da2952f0c4fa5c18e1fad319e2421e082..afb177d41d6bf7e17bff52570d8cff620c9c9924 100644
--- a/src/heap/gc-idle-time-handler.h
+++ b/src/heap/gc-idle-time-handler.h
@@ -116,7 +116,10 @@ class GCIdleTimeHandler {
   // If contexts are disposed at a higher rate a full gc is triggered.
   static const double kHighContextDisposalRate;
 
-  struct HeapState {
+  class HeapState {
+   public:
+    void Print();
+
     int contexts_disposed;
     double contexts_disposal_rate;
     size_t size_of_objects;