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

runtime/vm/thread_registry.cc

 // 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.
 
 #include "vm/thread_registry.h"
 
 #include "vm/isolate.h"
+#include "vm/json_stream.h"
 #include "vm/lockers.h"
 
 namespace dart {
 
 ThreadRegistry::~ThreadRegistry() {
   // Go over the free thread list and delete the thread objects.
   {
     MonitorLocker ml(threads_lock());
     // At this point the active list should be empty.
     ASSERT(active_list_ == NULL);
@@ skipping 66 matching lines @@
 void ThreadRegistry::PrepareForGC() {
   MonitorLocker ml(threads_lock());
   Thread* thread = active_list_;
   while (thread != NULL) {
     thread->PrepareForGC();
     thread = thread->next_;
   }
 }
 
 
+#ifndef PRODUCT
+void ThreadRegistry::PrintJSON(JSONStream* stream) const {
+  MonitorLocker ml(threads_lock());
+  JSONArray threads(stream);
+  PrintJSONHelper(&threads, active_list_);
+  PrintJSONHelper(&threads, free_list_);

[Cutch, 2016/12/08 22:25:54]

We shouldn't include the free list. These are Thread objects which aren't
actually owned anymore.

[bkonyi, 2016/12/08 22:42:01]

I'll go ahead and remove this then.

+}
+
+
+void ThreadRegistry::PrintJSONHelper(JSONArray* array, Thread* thread) const {
+  while (thread != NULL) {
+    array->AddValue(thread);
+    thread = thread->next_;
+  }
+}
+#endif
+
+
 void ThreadRegistry::AddToActiveListLocked(Thread* thread) {
   ASSERT(thread != NULL);
   ASSERT(threads_lock()->IsOwnedByCurrentThread());
   thread->next_ = active_list_;
   active_list_ = thread;
 }
 
 
 void ThreadRegistry::RemoveFromActiveListLocked(Thread* thread) {
   ASSERT(thread != NULL);
@@ skipping 33 matching lines @@
   ASSERT(thread->os_thread_ == NULL);
   ASSERT(thread->isolate_ == NULL);
   ASSERT(thread->heap_ == NULL);
   ASSERT(threads_lock()->IsOwnedByCurrentThread());
   // Add thread to the free list.
   thread->next_ = free_list_;
   free_list_ = thread;
 }
 
 }  // namespace dart