Inobject slack tracking is done on a per-closure basis instead of per-shared info basis.

test/cctest/test-mementos.cc

Index: test/cctest/test-mementos.cc
diff --git a/test/cctest/test-mementos.cc b/test/cctest/test-mementos.cc
index a377b4a4c6f31c0a8139f3dc9d1ae95ee37de817..4aee57c53e6257ced4f57b62b5be3bff9eab6cfd 100644
--- a/test/cctest/test-mementos.cc
+++ b/test/cctest/test-mementos.cc
@@ -89,10 +89,7 @@ TEST(PretenuringCallNew) {
   Isolate* isolate = CcTest::i_isolate();
   Heap* heap = isolate->heap();
 
-  // We need to create several instances to get past the slack-tracking
-  // phase, where mementos aren't emitted.
   int call_count = 10;
-  CHECK_GE(call_count, SharedFunctionInfo::kGenerousAllocationCount);
   i::ScopedVector<char> test_buf(1024);
   const char* program =
       "function f() {"
@@ -117,8 +114,8 @@ TEST(PretenuringCallNew) {
   CHECK_EQ(memento->map(), heap->allocation_memento_map());
 
   // Furthermore, how many mementos did we create? The count should match
-  // call_count - SharedFunctionInfo::kGenerousAllocationCount.
+  // call_count. Note, that mementos are allocated during the inobject slack
+  // tracking phase.
   AllocationSite* site = memento->GetAllocationSite();
-  CHECK_EQ(call_count - SharedFunctionInfo::kGenerousAllocationCount,
-           site->pretenure_create_count()->value());
+  CHECK_EQ(call_count, site->pretenure_create_count()->value());
 }