[Tracing] Add allocation register for heap profiling

base/trace_event/memory_profiler_allocation_register.cc

+// Copyright 2015 The Chromium 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 "base/trace_event/memory_profiler_allocation_register.h"
+
+namespace base {
+namespace trace_event {
+
+size_t RoundUpToPageSize(size_t size) {
+  size_t page_size = GetSystemPageSize();
+  return ((size + page_size - 1) / page_size) * page_size;
+}
+
+AllocationRegister::AllocationRegister() {}
+AllocationRegister::~AllocationRegister() {}
+
+void AllocationRegister::Insert(void* address,
+                                size_t size,
+                                AllocationContext context) {
+  Allocation* alloc = allocations_.Insert(reinterpret_cast<uintptr_t>(address));
+  alloc->size = size;
+  alloc->context = context;
+}
+
+void AllocationRegister::Remove(void* address) {
+  allocations_.Remove(reinterpret_cast<uintptr_t>(address));
+}
+
+AllocationRegister::AllocationRef AllocationRegister::ConstIterator::operator*()
+    const {
+  AllocationRef alloc_ref;
+  alloc_ref.address = reinterpret_cast<void*>((*iterator_).first);
+  alloc_ref.size = (*iterator_).second->size;
+  alloc_ref.context = &(*iterator_).second->context;
+  return alloc_ref;
+}
+
+}  // namespace trace_event
+}  // namespace base