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

runtime/vm/json_stream.cc

Index: runtime/vm/json_stream.cc
diff --git a/runtime/vm/json_stream.cc b/runtime/vm/json_stream.cc
index e75ba30f6c3458f82cf1505323a1db8ad01a31ad..4fe101d97c8a9b9ce4ff06f6a4853506731e4f22 100644
--- a/runtime/vm/json_stream.cc
+++ b/runtime/vm/json_stream.cc
@@ -14,6 +14,7 @@
 #include "vm/safepoint.h"
 #include "vm/service.h"
 #include "vm/service_event.h"
+#include "vm/thread_registry.h"
 #include "vm/timeline.h"
 #include "vm/unicode.h"
 
@@ -540,6 +541,24 @@ void JSONStream::PrintValue(Isolate* isolate, bool ref) {
 }
 
 
+void JSONStream::PrintValue(ThreadRegistry* reg) {
+  PrintCommaIfNeeded();
+  reg->PrintJSON(this);
+}
+
+
+void JSONStream::PrintValue(Thread* thread) {
+  PrintCommaIfNeeded();
+  thread->PrintJSON(this);
+}
+
+
+void JSONStream::PrintValue(Zone* zone) {
+  PrintCommaIfNeeded();
+  zone->PrintJSON(this);
+}
+
+
 void JSONStream::PrintValue(const TimelineEvent* timeline_event) {
   PrintCommaIfNeeded();
   timeline_event->PrintJSON(this);
@@ -663,6 +682,24 @@ void JSONStream::PrintProperty(const char* name, Isolate* isolate) {
 }
 
 
+void JSONStream::PrintProperty(const char* name, ThreadRegistry* reg) {
+  PrintPropertyName(name);
+  PrintValue(reg);
+}
+
+
+void JSONStream::PrintProperty(const char* name, Thread* thread) {
+  PrintPropertyName(name);
+  PrintValue(thread);
+}
+
+
+void JSONStream::PrintProperty(const char* name, Zone* zone) {
+  PrintPropertyName(name);
+  PrintValue(zone);
+}
+
+
 void JSONStream::PrintProperty(const char* name,
                                const TimelineEvent* timeline_event) {
   PrintPropertyName(name);