Add ExitFunnel to prepare for instrumenting browser exits.

components/browser_watcher/exit_funnel_win.h

Index: components/browser_watcher/exit_funnel_win.h
diff --git a/components/browser_watcher/exit_funnel_win.h b/components/browser_watcher/exit_funnel_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..251a31edac0b7b9ebde97d3af0f715db29391098
--- /dev/null
+++ b/components/browser_watcher/exit_funnel_win.h
@@ -0,0 +1,41 @@
+// 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.
+
+#ifndef COMPONENTS_BROWSER_WATCHER_END_SESSION_WIN_H_
+#define COMPONENTS_BROWSER_WATCHER_END_SESSION_WIN_H_
+
+#include "base/process/process_handle.h"
+#include "base/strings/string16.h"
+#include "base/win/registry.h"
+
+namespace browser_watcher {
+
+class ExitFunnel {
+ public:
+  ExitFunnel();
+  ~ExitFunnel();
+
+  // Initializes the exit funnel with |registry_path| and |process|.
+  // |process| must be open for PROCESS_QUERY_INFORMATION at least.
+  // Returns false on failure to create or open the registry path corresponding
+  // to |process|.
+  bool Init(const base::char16* registry_path, base::ProcessHandle process);
+
+  // Records |event_name| at the current time in registry for the process

[erikwright (departed), 2014/12/11 15:00:46]

the registry

[Sigurður Ásgeirsson, 2014/12/12 16:21:40]

Done.

+  // this instance is associated with. Returns false on failure to record the
+  // event.
+  bool RecordEvent(const base::char16* event_name);
+
+  // Records |event_name| at the current time in registry at |registry_path| for
+  // this process.
+  static bool RecordSingleEvent(const base::char16* registry_path,
+                                const base::char16* event_name);
+
+ private:
+  base::win::RegKey key_;
+};
+
+}  // namespace browser_watcher
+
+#endif  // COMPONENTS_BROWSER_WATCHER_END_SESSION_WIN_H_