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

runtime/vm/thread.cc

Index: runtime/vm/thread.cc
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index 709d735156f35122f439b1abe52a1709a25d7ee9..944b3504c9e663cb5c603d82d598d118132bea86 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -8,6 +8,7 @@
 #include "vm/dart_api_state.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
+#include "vm/json_stream.h"
 #include "vm/lockers.h"
 #include "vm/log.h"
 #include "vm/message_handler.h"
@@ -205,6 +206,31 @@ void Thread::InitVMConstants() {
 }
 
 
+#ifndef RELEASE

[Cutch, 2016/12/06 19:11:15]

dito

[bkonyi, 2016/12/08 18:04:14]

Done.

+// Collect information about each individual zone associated with this thread.
+void Thread::PrintToJSONObject(JSONObject* obj) {
+  intptr_t size = 0;
+  Zone* zone = zone_;
+  while (zone != NULL) {
+    size += zone->SizeInBytes();
+    zone = zone->previous();
+  }
+  obj->AddPropertyF("thread_address", "0x%" Px "",

[Cutch, 2016/12/06 19:11:15]

we use dartCamelCase for service protocol property names.

Not sure why we are printing the thread address here.

[bkonyi, 2016/12/08 18:04:14]

Done.

+                    reinterpret_cast<uword>(this));
+  obj->AddPropertyF("thread_zone_size_total", "%ld", size);
+  {
+    JSONArray zone_info_array(obj, "zones");
+    zone = zone_;
+    while (zone != NULL) {
+      JSONObject zone_obj(&zone_info_array);
+      zone->PrintToJSONObject(&zone_obj);
+      zone = zone->previous();
+    }
+  }
+}
+#endif
+
+
 RawGrowableObjectArray* Thread::pending_functions() {
   if (pending_functions_ == GrowableObjectArray::null()) {
     pending_functions_ = GrowableObjectArray::New(Heap::kOld);