Track live instance and allocation counts for classes

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
diff --git a/runtime/vm/assembler_x64.h b/runtime/vm/assembler_x64.h
index 9daaf6ca603bec7323e47cf937dac18866cb7d3a..c2a692170aeda5e373804c8a6dd71586a988334b 100644
--- a/runtime/vm/assembler_x64.h
+++ b/runtime/vm/assembler_x64.h
@@ -825,6 +825,13 @@ class Assembler : public ValueObject {
   //   L:
   static const intptr_t kEntryPointToPcMarkerOffset = 9;
 
+  void BumpAllocationCount(Heap::Space space,
+                           intptr_t cid);
+
+  void BumpAllocationCount(Heap::Space space,
+                           intptr_t cid,
+                           Register size_reg);
+
   // Inlined allocation of an instance of class 'cls', code has no runtime
   // calls. Jump to 'failure' if the instance cannot be allocated here.
   // Allocated instance is returned in 'instance_reg'.