Add out-of-process memory logging stream parsing.

chrome/profiling/backtrace_storage.cc

+// Copyright 2017 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 "chrome/profiling/backtrace_storage.h"
+
+#include "chrome/profiling/backtrace.h"
+
+namespace profiling {
+
+BacktraceStorage::BacktraceStorage() {}
+
+BacktraceStorage::~BacktraceStorage() {}
+
+BacktraceStorage::Key BacktraceStorage::Insert(std::vector<Address>&& bt) {
+  base::AutoLock lock(lock_);
+
+  BacktraceStorage::Key key =
+      backtraces_.insert(Backtrace(std::move(bt))).first;
+  key->AddRef();
+  return key;
+}
+
+void BacktraceStorage::Free(const Key& key) {
+  base::AutoLock lock(lock_);
+  if (!key->Release())
+    backtraces_.erase(key);
+}
+
+void BacktraceStorage::Free(const std::vector<Key>& keys) {
+  base::AutoLock lock(lock_);
+  for (size_t i = 0; i < keys.size(); i++) {
+    if (!keys[i]->Release())
+      backtraces_.erase(keys[i]);
+  }
+}
+
+const Backtrace& BacktraceStorage::GetBacktraceForKey(const Key& key) const {
+  // Since the caller should own a reference to the key and the container has
+  // stable iterators, we can access without a lock.
+  return *key;
+}
+
+}  // namespace profiling