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

test/cctest/test-mementos.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 71 matching lines @@
 
 TEST(PretenuringCallNew) {
   CcTest::InitializeVM();
   if (!i::FLAG_allocation_site_pretenuring) return;
   if (!i::FLAG_pretenuring_call_new) return;
 
   v8::HandleScope scope(CcTest::isolate());
   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() {"
       "  this.a = 3;"
       "  this.b = {};"
       "  return this;"
       "};"
       "var a;"
       "for(var i = 0; i < %d; i++) {"
       "  a = new f();"
       "}"
       "a;";
   i::OS::SNPrintF(test_buf, program, call_count);
   v8::Local<v8::Value> res = CompileRun(test_buf.start());
   Handle<JSObject> o =
       v8::Utils::OpenHandle(*v8::Handle<v8::Object>::Cast(res));
 
   // The object of class f should have a memento secreted behind it.
   Address memento_address = o->address() + o->map()->instance_size();
   AllocationMemento* memento =
       reinterpret_cast<AllocationMemento*>(memento_address + kHeapObjectTag);
   CHECK_EQ(memento->map(), heap->allocation_memento_map());
 
   // Furthermore, how many mementos did we create? The count should match
-  // call_count. Note, that mementos are allocated during the inobject slack
-  // tracking phase.
+  // call_count - SharedFunctionInfo::kGenerousAllocationCount.
   AllocationSite* site = memento->GetAllocationSite();
-  CHECK_EQ(call_count, site->pretenure_create_count()->value());
+  CHECK_EQ(call_count - SharedFunctionInfo::kGenerousAllocationCount,
+           site->pretenure_create_count()->value());
 }