Revert of Preprocess structured stack trace on GC to get rid of code reference.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index d4038c78e52e5b284d2a0fc6e6d996afcf938014..e9379ac5658c9653cb21023f180d567a2364c068 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -706,26 +706,6 @@
 }
 
 
-void Heap::PreprocessStackTraces() {
-  if (!weak_stack_trace_list()->IsWeakFixedArray()) return;
-  WeakFixedArray* array = WeakFixedArray::cast(weak_stack_trace_list());
-  int length = array->Length();
-  for (int i = 0; i < length; i++) {
-    if (array->IsEmptySlot(i)) continue;
-    FixedArray* elements = FixedArray::cast(array->Get(i));
-    for (int j = 1; j < elements->length(); j += 4) {
-      Code* code = Code::cast(elements->get(j + 2));
-      int offset = Smi::cast(elements->get(j + 3))->value();
-      Address pc = code->address() + offset;
-      int pos = code->SourcePosition(pc);
-      elements->set(j + 2, Smi::FromInt(pos));
-    }
-    array->Clear(i);
-  }
-  array->Compact();
-}
-
-
 void Heap::HandleGCRequest() {
   if (incremental_marking()->request_type() ==
       IncrementalMarking::COMPLETE_MARKING) {
@@ -1292,8 +1272,6 @@
   isolate_->counters()->objs_since_last_full()->Set(0);
 
   incremental_marking()->Epilogue();
-
-  PreprocessStackTraces();
 }
 
 
@@ -3104,8 +3082,6 @@
   cell->set_value(Smi::FromInt(Isolate::kArrayProtectorValid));
   set_array_protector(*cell);
 
-  set_weak_stack_trace_list(Smi::FromInt(0));
-
   set_allocation_sites_scratchpad(
       *factory->NewFixedArray(kAllocationSiteScratchpadSize, TENURED));
   InitializeAllocationSitesScratchpad();
@@ -3142,7 +3118,6 @@
     case kDetachedContextsRootIndex:
     case kWeakObjectToCodeTableRootIndex:
     case kRetainedMapsRootIndex:
-    case kWeakStackTraceListRootIndex:
 // Smi values
 #define SMI_ENTRY(type, name, Name) case k##Name##RootIndex:
       SMI_ROOT_LIST(SMI_ENTRY)