Identify the hung thread using the Wait Chain Traversal API

chrome/chrome_watcher/wait_chain_util_win.h

Index: chrome/chrome_watcher/wait_chain_util_win.h
diff --git a/chrome/chrome_watcher/wait_chain_util_win.h b/chrome/chrome_watcher/wait_chain_util_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..735ac70fe3bcea893f47bdb64e6ec6866c2e5041
--- /dev/null
+++ b/chrome/chrome_watcher/wait_chain_util_win.h
@@ -0,0 +1,26 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.

[manzagop (departed), 2016/03/24 19:36:37]

A few questions about form:
- What determines whether code should go in a component or not? Eg
components/browser_watcher?
- when should you use the _win suffix?
- should this be in a namespace?

Sidenote which may affect the answer: I'd like to use this at he time of RDV.

[Patrick Monette, 2016/03/24 23:21:04]

Lets not mess with components!

The _win suffix isn't necessary here because the whole chrome_watcher stuff is
windows specific but I like to denote windows specific files with it.

And I don't think there is a namespace for the chrome/ folder so that's why I
didn't put one.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_CHROME_WATCHER_WAIT_CHAIN_UTIL_WIN_H_
+#define CHROME_CHROME_WATCHER_WAIT_CHAIN_UTIL_WIN_H_
+
+#include <windows.h>
+#include <wct.h>
+
+#include <vector>
+
+// Get the wait chain for the |thread_id|. Also specifies if the |wait_chain|
+// contains a deadlock.Returns true on success.

[manzagop (departed), 2016/03/24 19:36:36]

nit: missing whitespace

[Patrick Monette, 2016/03/24 23:21:04]

Done.

+//
+// From MSDN: A wait chain is an alternating sequence of threads and
+// synchronization objects; each thread waits for the object that follows it,
+// which is owned by the subsequent thread in the chain.
+bool GetThreadWaitChain(DWORD thread_id,
+                        std::vector<WAITCHAIN_NODE_INFO>* wait_chain,
+                        bool* is_deadlock);
+
+// Returns a string that represent the node for a wait chain.

[manzagop (departed), 2016/03/24 19:36:37]

nit: represent*s*

[Patrick Monette, 2016/03/24 23:21:04]

Done.

+std::wstring WaitChainNodeToString(const WAITCHAIN_NODE_INFO& node);
+
+#endif  // CHROME_CHROME_WATCHER_WAIT_CHAIN_UTIL_WIN_H_