Implement a heap profiler for the Dart managed heap.

runtime/vm/heap.h

Index: runtime/vm/heap.h
diff --git a/runtime/vm/heap.h b/runtime/vm/heap.h
index a2f4f2b3f0bc288dbc47262a602e50727f700e2c..5df69853ebbdb2a61dff6e3c1b720b38a1f73cb7 100644
--- a/runtime/vm/heap.h
+++ b/runtime/vm/heap.h
@@ -114,6 +114,9 @@ class Heap {
   // Print heap sizes.
   void PrintSizes() const;
 
+  // Generates a profile of the current and VM isolate heaps.

[turnidge, 2012/05/29 17:50:01]

Out of curiosity -- by including the VM isolate heap in all of our per-isolate
heap profiles, is there some chance tools will get a bloated sense of the
per-isolate space requirements?  Maybe this doesn't matter.

[cshapiro, 2012/06/01 04:27:02]

Based on experience, the most common use of this data will be to examine a heap
post-OOM to understand what retained storage.  In that situation it is usually
okay for the vm isolate data to be included as it will be dwarfed by the
application heap.  

I think having a snapshot of just the current isolate would be a good option to
have.  Once the profiler becomes more complete I would like to add a flag to
control whether the VM isolate contents are emitted.

+  void Profile(Dart_HeapProfileWriteCallback callback, void* stream) const;
+
  private:
   Heap();