Introduce mechanism to record an allocation of a class

runtime/vm/profiler.h

Index: runtime/vm/profiler.h
diff --git a/runtime/vm/profiler.h b/runtime/vm/profiler.h
index cea7bd5b1fce26b9e22851c327c3bd683890104f..b4a4d0b745eb653b584dbccd376f47d5cee0cd6f 100644
--- a/runtime/vm/profiler.h
+++ b/runtime/vm/profiler.h
@@ -44,6 +44,8 @@ class Profiler : public AllStatic {
     return sample_buffer_;
   }
 
+  static void RecordAllocation(Isolate* isolate, intptr_t cid);
+
  private:
   static bool initialized_;
   static Monitor* monitor_;
@@ -308,6 +310,11 @@ class Sample {
     metadata_ = metadata;
   }
 
+  void SetAllocationCid(intptr_t cid) {
+    set_is_allocation_sample(true);
+    set_metadata(cid);
+  }
+
   static void InitOnce();
 
   static intptr_t instance_size() {