Created methods to surface zone memory information for each isolate and thread in JSON.

runtime/vm/thread_registry.h

Index: runtime/vm/thread_registry.h
diff --git a/runtime/vm/thread_registry.h b/runtime/vm/thread_registry.h
index eb2d327f64ebac1a7ce8828ea3eb341fcba6baaa..2b92681ec582d3f4886cae2c7ca5d429c1fb9c23 100644
--- a/runtime/vm/thread_registry.h
+++ b/runtime/vm/thread_registry.h
@@ -12,6 +12,11 @@
 #include "vm/stack_frame.h"
 #include "vm/thread.h"
 
+#if defined(DEBUG)

[zra, 2016/12/08 18:54:13]

#ifndef PRODUCT?

[bkonyi, 2016/12/08 20:58:32]

Done.

+class JSONStream;
+class JSONArray;
+#endif
+
 namespace dart {
 
 // Unordered collection of threads relating to a particular isolate.
@@ -28,6 +33,10 @@ class ThreadRegistry {
   void PrepareForGC();
   Thread* mutator_thread() const { return mutator_thread_; }
 
+#if defined(DEBUG)

[zra, 2016/12/08 18:54:13]

ditto

[bkonyi, 2016/12/08 20:58:32]

Done.

+  void PrintJSON(JSONStream* stream, bool ref = true) const;

[zra, 2016/12/08 18:54:13]

ditto

[bkonyi, 2016/12/08 20:58:32]

Done.

+#endif
+
  private:
   Thread* active_list() const { return active_list_; }
   Monitor* threads_lock() const { return threads_lock_; }
@@ -39,6 +48,10 @@ class ThreadRegistry {
   Thread* GetFromFreelistLocked(Isolate* isolate);
   void ReturnToFreelistLocked(Thread* thread);
 
+#if defined(DEBUG)

[zra, 2016/12/08 18:54:13]

ditto

[bkonyi, 2016/12/08 20:58:32]

Done.

+  void PrintJSONHelper(JSONArray* array, Thread* thread) const;
+#endif
+
   // This monitor protects the threads list for an isolate, it is used whenever
   // we need to iterate over threads (both active and free) in an isolate.
   Monitor* threads_lock_;