Add ability to retrieve a thread_name given a thread_id.

base/threading/thread_id_name_manager.cc

Index: base/threading/thread_id_name_manager.cc
diff --git a/base/threading/thread_id_name_manager.cc b/base/threading/thread_id_name_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4374aa52bc153858656219e071aebb046d520d0e
--- /dev/null
+++ b/base/threading/thread_id_name_manager.cc
@@ -0,0 +1,46 @@
+// Copyright (c) 2012 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/threading/thread_id_name_manager.h"
+
+#include "base/memory/singleton.h"
+
+namespace base {
+
+ThreadIdNameManager::ThreadIdNameManager() {
+}
+
+ThreadIdNameManager::~ThreadIdNameManager() {
+}
+
+ThreadIdNameManager* ThreadIdNameManager::GetInstance() {
+  return Singleton<ThreadIdNameManager>::get();
+}
+
+bool ThreadIdNameManager::GetNameForId(PlatformThreadId id, std::string* name) {
+  if (name == NULL)
+    return false;
+
+  base::AutoLock locked(lock_);
+
+  std::map<PlatformThreadId, std::string>::const_iterator it;
+  it = id_to_name_.find(id);
+  if (it == id_to_name_.end())
+    return false;
+
+  *name = it->second;
+  return true;
+}
+
+void ThreadIdNameManager::SetNameForId(PlatformThreadId id, std::string name) {
+  base::AutoLock locked(lock_);
+  id_to_name_[id] = name;
+}
+
+void ThreadIdNameManager::RemoveNameForId(PlatformThreadId id) {
+  base::AutoLock locked(lock_);
+  id_to_name_.erase(id);
+}
+
+}  // namespace base