Track live instance and allocation counts for classes

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index f42247e34824fbaa4c40cd7069c7e777c0e1e2a1..b20611a054e4f9d8aec5b90a09fddbaa6aa739ea 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -31,6 +31,7 @@ class Function;
 class HandleScope;
 class HandleVisitor;
 class Heap;
+class HeapClassStatistics;
 class ICData;
 class Instance;
 class LongJump;
@@ -343,6 +344,10 @@ class Isolate : public BaseIsolate {
     return object_id_ring_;
   }
 
+  HeapClassStatistics* heap_class_stats() {
+    return heap_class_stats_;
+  }
+
   DeoptContext* deopt_context() const { return deopt_context_; }
   void set_deopt_context(DeoptContext* value) {
     ASSERT(value == NULL || deopt_context_ == NULL);
@@ -421,6 +426,9 @@ class Isolate : public BaseIsolate {
   // Ring buffer of objects assigned an id.
   ObjectIdRing* object_id_ring_;
 
+  // Heap statistics by class id
+  HeapClassStatistics* heap_class_stats_;
+
   // Reusable handles support.
 #define REUSABLE_HANDLE_FIELDS(object)                                         \
   object* object##_handle_;                                                    \