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

runtime/vm/service.cc

Index: runtime/vm/service.cc
diff --git a/runtime/vm/service.cc b/runtime/vm/service.cc
index dce3eace094526f7a174917c6e957cd7111e8aa4..aa01c894def742bdaa9eb4996ed1e971b66e9129 100644
--- a/runtime/vm/service.cc
+++ b/runtime/vm/service.cc
@@ -3758,19 +3758,21 @@ static bool GetVersion(Thread* thread, JSONStream* js) {
 
 class ServiceIsolateVisitor : public IsolateVisitor {
  public:
-  explicit ServiceIsolateVisitor(JSONArray* jsarr) : jsarr_(jsarr) {}
+  explicit ServiceIsolateVisitor(JSONArray* jsarr, bool ref = true)

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

Unless I'm missing something, this class only has one instantiation, so I think
we don't need to use an optional argument here.

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

You're right, it's only instantiated once. I've removed the ref parameter since
it should always be false given the implementation of PrintJSONForVM

+      : jsarr_(jsarr), ref_(ref) {}
 
   virtual ~ServiceIsolateVisitor() {}
 
   void VisitIsolate(Isolate* isolate) {
     if ((isolate != Dart::vm_isolate()) &&
         !ServiceIsolate::IsServiceIsolateDescendant(isolate)) {
-      jsarr_->AddValue(isolate);
+      jsarr_->AddValue(isolate, ref_);
     }
   }
 
  private:
   JSONArray* jsarr_;
+  bool ref_;
 };
 
 
@@ -3800,7 +3802,7 @@ void Service::PrintJSONForVM(JSONStream* js, bool ref) {
   // Construct the isolate list.
   {
     JSONArray jsarr(&jsobj, "isolates");
-    ServiceIsolateVisitor visitor(&jsarr);
+    ServiceIsolateVisitor visitor(&jsarr, ref);
     Isolate::VisitIsolates(&visitor);
   }
 }