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..79bed389f26baab249bea243385126083ebd3e04
--- /dev/null
+++ b/base/threading/thread_id_name_manager.cc
@@ -0,0 +1,72 @@
+// 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 <stdlib.h>
+#include <string.h>
+
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+
+namespace base {
+
+ThreadIdNameManager::ThreadIdNameManager()
+    : current_version_(1) {
+}
+
+ThreadIdNameManager::~ThreadIdNameManager() {
+}
+
+ThreadIdNameManager* ThreadIdNameManager::GetInstance() {
+  return Singleton<ThreadIdNameManager,
+      LeakySingletonTraits<ThreadIdNameManager> >::get();
+}
+
+const char* ThreadIdNameManager::GetNameForId(PlatformThreadId id) {
+  base::AutoLock locked(lock_);
+  DCHECK(id_to_name_.count(id));
+  return id_to_name_[id];
+}
+
+void ThreadIdNameManager::SetNameForId(PlatformThreadId id, const char* name) {
+  char* dup_name = strdup(name);
+  char* orig_name = NULL;
+  {
+    base::AutoLock locked(lock_);
+    if (id_to_name_.count(id))
+      orig_name = id_to_name_[id];
+
+    id_to_name_[id] = dup_name;
+    id_to_version_[id] = current_version_++;
+  }
+  free(orig_name);
+}
+
+void ThreadIdNameManager::RemoveNameForId(PlatformThreadId id) {
+  if (id == base::kInvalidThreadId)
+    return;
+
+  char* old_name = NULL;
+  {
+    base::AutoLock locked(lock_);
+    DCHECK(id_to_name_.count(id));
+
+    old_name = id_to_name_[id];
+    id_to_name_.erase(id);
+    id_to_version_.erase(id);
+  }
+  free(old_name);
+}
+
+uint32 ThreadIdNameManager::GetVersionForId(PlatformThreadId id) {
+  if (id == base::kInvalidThreadId)
+    return 0;
+
+  base::AutoLock locked(lock_);
+  DCHECK(id_to_version_.count(id));
+  return id_to_version_[id];
+}
+
+}  // namespace base