Added methods to surface number of zone and scoped handles for each isolate.

runtime/vm/thread.cc

Index: runtime/vm/thread.cc
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index 1b3428eaa62eba6a88e01859b9b294528db1cce3..e9381014d894ee75b400597a3994e6d3937bc1fd 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -753,8 +753,8 @@ bool Thread::IsValidLocalHandle(Dart_Handle object) const {
 }
 
 
-int Thread::CountLocalHandles() const {
-  int total = 0;
+intptr_t Thread::CountLocalHandles() const {
+  intptr_t total = 0;
   ApiLocalScope* scope = api_top_scope_;
   while (scope != NULL) {
     total += scope->local_handles()->CountHandles();
@@ -764,6 +764,30 @@ int Thread::CountLocalHandles() const {
 }
 
 
+intptr_t Thread::CountZoneHandles() const {
+  intptr_t count = 0;
+  Zone* zone = zone_;
+  while (zone != NULL) {
+    count += zone->handles()->CountZoneHandles();
+    zone = zone->previous();
+  }
+  ASSERT(count >= 0);
+  return count;
+}
+
+
+intptr_t Thread::CountScopedHandles() const {
+  intptr_t count = 0;
+  Zone* zone = zone_;
+  while (zone != NULL) {
+    count += zone->handles()->CountScopedHandles();
+    zone = zone->previous();
+  }
+  ASSERT(count >= 0);
+  return count;
+}
+
+
 int Thread::ZoneSizeInBytes() const {
   int total = 0;
   ApiLocalScope* scope = api_top_scope_;