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

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index aa864b66ba591f2ff4046834be81ddf68aa9c699..f2c209edc63940e00c1f8f224106ff7d80c38bd2 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -1699,6 +1699,7 @@ class PagedSpace : public Space {
   // Allocate the requested number of bytes in the space if possible, return a
   // failure object if not.
   MUST_USE_RESULT inline MaybeObject* AllocateRaw(int size_in_bytes);
+  MUST_USE_RESULT inline MaybeObject* AllocateRawForMigration(int size_in_bytes);
 
   virtual bool ReserveSpace(int bytes);
 
@@ -1879,6 +1880,9 @@ class PagedSpace : public Space {
 
   friend class PageIterator;
   friend class SweeperThread;
+
+ private:
+  inline HeapObject* AllocateRawHelper(int size_in_bytes);
 };