Track JS allocations as they arrive with no affection on performance when tracking is switched off

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 12200740a0becb3ff604b6622be73f73226badfc..95be8d6757d6871ccaddb26ea40f6839037a056d 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -65,6 +65,13 @@ class AssemblerBase: public Malloced {
   bool emit_debug_code() const { return emit_debug_code_; }
   void set_emit_debug_code(bool value) { emit_debug_code_ = value; }
 
+  bool emit_allocations_tracking_code() const {
+    return emit_allocations_tracking_code_;
+  }
+  void set_emit_allocations_tracking_code(bool value) {
+    emit_allocations_tracking_code_ = value;
+  }
+
   bool predictable_code_size() const { return predictable_code_size_; }
   void set_predictable_code_size(bool value) { predictable_code_size_ = value; }
 
@@ -99,6 +106,7 @@ class AssemblerBase: public Malloced {
   int jit_cookie_;
   uint64_t enabled_cpu_features_;
   bool emit_debug_code_;
+  bool emit_allocations_tracking_code_;
   bool predictable_code_size_;
 };
 
@@ -729,6 +737,9 @@ class ExternalReference BASE_EMBEDDED {
 
   static ExternalReference get_make_code_young_function(Isolate* isolate);
 
+  // New heap objects tracking support.
+  static ExternalReference record_object_allocation_function(Isolate* isolate);
+
   // Deoptimization support.
   static ExternalReference new_deoptimizer_function(Isolate* isolate);
   static ExternalReference compute_output_frames_function(Isolate* isolate);