Track live instance and allocation counts for classes

runtime/vm/heap.h

Index: runtime/vm/heap.h
diff --git a/runtime/vm/heap.h b/runtime/vm/heap.h
index 703c2650c5728d32e3bee8424ccf3f0378e27573..545def1c37a34db6309d308391839c3c398e1f72 100644
--- a/runtime/vm/heap.h
+++ b/runtime/vm/heap.h
@@ -165,7 +165,10 @@ class Heap {
   // Return amount of memory used and capacity in a space.
   intptr_t UsedInWords(Space space) const;
   intptr_t CapacityInWords(Space space) const;
+  // Return the amount of GCing in microseconds.
+  int64_t GCTimeInMicros(Space space) const;
 
+  intptr_t Collections(Space space) const;
   // Returns the [lowest, highest) addresses in the heap.
   void StartEndAddress(uword* start, uword* end) const;
 
@@ -229,6 +232,8 @@ class Heap {
     return size <= kNewAllocatableSize;
   }
 
+  void PrintToJSONObject(Space space, JSONObject* object) const;
+
  private:
   class GCStats : public ValueObject {
    public:
@@ -274,6 +279,7 @@ class Heap {
   void RecordAfterGC();
   void PrintStats();
   void UpdateObjectHistogram();
+  void UpdateClassHeapStatsBeforeGC(Heap::Space space);
 
   // The different spaces used for allocation.
   Scavenger* new_space_;