Revert of [heap] Fine-grained JSArrayBuffer tracking

src/heap/array-buffer-tracker-inl.h

-// Copyright 2016 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "src/heap/array-buffer-tracker.h"
-#include "src/heap/heap.h"
-#include "src/heap/mark-compact.h"
-#include "src/isolate.h"
-
-namespace v8 {
-namespace internal {
-
-template <typename Callback>
-void LocalArrayBufferTracker::Process(Callback callback) {
-  JSArrayBuffer* new_buffer = nullptr;
-  size_t freed_memory = 0;
-  for (TrackingMap::iterator it = live_.begin(); it != live_.end();) {
-    switch (callback(it->first, &new_buffer)) {
-      case kKeepEntry:
-        it++;
-        break;
-      case kKeepAndUpdateEntry:
-        DCHECK_NOT_NULL(new_buffer);
-        Page::FromAddress(new_buffer->address())
-            ->local_tracker()
-            ->AddLive(new_buffer, it->second);
-        live_.erase(it++);
-        break;
-      case kRemoveEntry:
-        heap_->isolate()->array_buffer_allocator()->Free(it->second.first,
-                                                         it->second.second);
-        freed_memory += it->second.second;
-        live_.erase(it++);
-        break;
-      default:
-        UNREACHABLE();
-    }
-  }
-  if (freed_memory > 0) {
-    heap_->update_amount_of_external_allocated_freed_memory(
-        static_cast<intptr_t>(freed_memory));
-  }
-  not_yet_discovered_.clear();
-  started_ = false;
-}
-
-template <LocalArrayBufferTracker::LivenessIndicator liveness_indicator>
-void LocalArrayBufferTracker::ScanAndFreeDead() {
-  switch (liveness_indicator) {
-    case kForwardingPointer:
-      Process([](JSArrayBuffer* old_buffer, JSArrayBuffer** new_buffer) {
-        MapWord map_word = old_buffer->map_word();
-        if (map_word.IsForwardingAddress()) {
-          *new_buffer = JSArrayBuffer::cast(map_word.ToForwardingAddress());
-          return LocalArrayBufferTracker::kKeepAndUpdateEntry;
-        }
-        return LocalArrayBufferTracker::kRemoveEntry;
-      });
-      break;
-    case kMarkBit:
-      Process([](JSArrayBuffer* old_buffer, JSArrayBuffer**) {
-        if (Marking::IsBlackOrGrey(Marking::MarkBitFrom(old_buffer))) {
-          return LocalArrayBufferTracker::kKeepEntry;
-        }
-        return LocalArrayBufferTracker::kRemoveEntry;
-      });
-      break;
-    default:
-      UNREACHABLE();
-  }
-}
-
-}  // namespace internal
-}  // namespace v8