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

runtime/vm/zone.cc

 // Copyright (c) 2012, 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/zone.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
 #include "vm/handles_impl.h"
@@ skipping 242 matching lines @@
   va_end(args);
   return buffer;
 }
 
 
 char* Zone::VPrint(const char* format, va_list args) {
   return OS::VSCreate(this, format, args);
 }
 
 
+#ifndef PRODUCT
+void Zone::PrintJSON(JSONStream* stream) const {
+  JSONObject jsobj(stream);
+  intptr_t capacity = SizeInBytes();
+  intptr_t used_size = UsedSizeInBytes();
+  jsobj.AddProperty("type", "_Zone");
+  jsobj.AddProperty("capacity", capacity);
+  jsobj.AddProperty("used", used_size);
+}
+#endif
+
+
 StackZone::StackZone(Thread* thread) : StackResource(thread), zone_() {
   if (FLAG_trace_zones) {
     OS::PrintErr("*** Starting a new Stack zone 0x%" Px "(0x%" Px ")\n",
                  reinterpret_cast<intptr_t>(this),
                  reinterpret_cast<intptr_t>(&zone_));
   }
   zone_.Link(thread->zone());
   thread->set_zone(&zone_);
 }
 
 
 StackZone::~StackZone() {
   ASSERT(thread()->zone() == &zone_);
   thread()->set_zone(zone_.previous_);
   if (FLAG_trace_zones) {
     OS::PrintErr("*** Deleting Stack zone 0x%" Px "(0x%" Px ")\n",
                  reinterpret_cast<intptr_t>(this),
                  reinterpret_cast<intptr_t>(&zone_));
   }
 }
 
 }  // namespace dart