Instrument some of the exit paths likely to suffer hangs.

chrome/chrome_watcher/chrome_watcher_main.cc

 // Copyright (c) 2014 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 <windows.h>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/logging_win.h"
+#include "base/process/process_handle.h"
 #include "base/template_util.h"
 #include "components/browser_watcher/exit_code_watcher_win.h"
+#include "components/browser_watcher/exit_funnel_win.h"
 #include "components/browser_watcher/watcher_main_api_win.h"
 
 namespace {
 
 // Use the same log facility as Chrome for convenience.
 // {7FE69228-633E-4f06-80C1-527FEA23E3A7}
 const GUID kChromeWatcherTraceProviderName = {
     0x7fe69228, 0x633e, 0x4f06,
         { 0x80, 0xc1, 0x52, 0x7f, 0xea, 0x23, 0xe3, 0xa7 } };
 
@@ skipping 13 matching lines @@
   // chrome.exe in order to report its exit status.
   // TODO(siggi): Does this (windowless) process need to register a console
   //     handler too, in order to get notice of logoff events?
   ::SetProcessShutdownParameters(0x100, SHUTDOWN_NORETRY);
 
   browser_watcher::ExitCodeWatcher exit_code_watcher(registry_path);
   int ret = 1;
   // Attempt to wait on our parent process, and record its exit status.
   if (exit_code_watcher.ParseArguments(
         *base::CommandLine::ForCurrentProcess())) {
+    base::ProcessHandle dupe = base::kNullProcessHandle;

[rvargas (doing something else), 2014/12/13 01:32:53]

It would be nice to use base::Process here... but that can be done afterwards.

+    // Duplicate the process handle for the exit funnel due to the wonky
+    // process handle lifetime management in base.
+    if (!::DuplicateHandle(base::GetCurrentProcessHandle(),
+                           exit_code_watcher.process(),
+                           base::GetCurrentProcessHandle(),
+                           &dupe,
+                           0,
+                           FALSE,
+                           DUPLICATE_SAME_ACCESS)) {
+      dupe = base::kNullProcessHandle;
+    }
+
     // Wait on the process.
     exit_code_watcher.WaitForExit();
+
+    if (dupe != base::kNullProcessHandle) {
+      browser_watcher::ExitFunnel funnel;
+      funnel.Init(registry_path, dupe);
+      funnel.RecordEvent(L"BrowserExit");
+
+      base::CloseProcessHandle(dupe);
+    }
+
     ret = 0;
   }
 
   // Wind logging down.
   logging::LogEventProvider::Uninitialize();
 
   return ret;
 }
 
 static_assert(base::is_same<decltype(&WatcherMain),
                             browser_watcher::WatcherMainFunction>::value,
               "WatcherMain() has wrong type");