Moved zones and zone related stuff in its own directory.

src/zone/accounting-allocator.cc

+// 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/zone/accounting-allocator.h"
+
+#include <cstdlib>
+
+#if V8_LIBC_BIONIC
+#include <malloc.h>  // NOLINT
+#endif
+
+namespace v8 {
+namespace internal {
+
+Segment* AccountingAllocator::AllocateSegment(size_t bytes) {
+  void* memory = malloc(bytes);
+  if (memory) {
+    base::AtomicWord current =
+        base::NoBarrier_AtomicIncrement(&current_memory_usage_, bytes);
+    base::AtomicWord max = base::NoBarrier_Load(&max_memory_usage_);
+    while (current > max) {
+      max = base::NoBarrier_CompareAndSwap(&max_memory_usage_, max, current);
+    }
+  }
+  return reinterpret_cast<Segment*>(memory);
+}
+
+void AccountingAllocator::FreeSegment(Segment* memory) {
+  base::NoBarrier_AtomicIncrement(
+      &current_memory_usage_, -static_cast<base::AtomicWord>(memory->size()));
+  free(memory);
+}
+
+size_t AccountingAllocator::GetCurrentMemoryUsage() const {
+  return base::NoBarrier_Load(&current_memory_usage_);
+}
+
+size_t AccountingAllocator::GetMaxMemoryUsage() const {
+  return base::NoBarrier_Load(&max_memory_usage_);
+}
+
+}  // namespace internal
+}  // namespace v8