Add ExitFunnel to prepare for instrumenting browser exits.

components/browser_watcher/exit_funnel_win.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 "components/browser_watcher/exit_funnel_win.h"
+
+#include <windows.h>
+
+#include "base/strings/string16.h"

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

dup from header

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

Done.

+#include "base/strings/stringprintf.h"
+#include "base/time/time.h"
+#include "base/win/registry.h"

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

dup from header

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

Done.

+
+namespace browser_watcher {
+
+ExitFunnel::ExitFunnel() {
+}
+
+ExitFunnel::~ExitFunnel() {
+}
+
+bool ExitFunnel::Init(const base::char16* registry_path,
+                      base::ProcessHandle process_handle) {
+  // Concatenate the pid and the creation time of the process to get a
+  // unique key name.
+  base::ProcessId pid = base::GetProcId(process_handle);
+
+  FILETIME creation_time = {};
+  FILETIME dummy = {};
+  if (!::GetProcessTimes(process_handle, &creation_time,
+                         &dummy, &dummy, &dummy)) {
+    LOG(ERROR) << "Invalid process handle, can't get process times.";
+    return false;
+  }
+
+  base::string16 key_name = registry_path;
+  base::StringAppendF(&key_name, L"\\%d-%lld", pid,

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

Personally I find this harder to read than:

base::string16 key_name = registry_path + L"\\" + base::UintToString(pid) + L"-"
+ base::UintToString(base::Time::FromFileTime(...).ToInternalValue();

But you might reasonably disagree.

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

Acknowledged.

+      base::Time::FromFileTime(creation_time).ToInternalValue());
+
+  LONG res = key_.Create(HKEY_CURRENT_USER, key_name.c_str(), KEY_SET_VALUE);
+  if (res != ERROR_SUCCESS) {
+    LOG(ERROR) << "Unable to create key " << key_name << " error " << res;
+    return false;
+  }
+
+  return true;
+}
+
+bool ExitFunnel::RecordEvent(const base::char16* event_name) {
+  int64 now = base::Time::Now().ToInternalValue();
+
+  LONG res = key_.WriteValue(event_name, &now, sizeof(now), REG_QWORD);
+  if (res != ERROR_SUCCESS) {
+    LOG(ERROR) << "Unable to write value " << event_name << " error " << res;
+    return false;
+  }
+
+  return true;
+}
+
+bool ExitFunnel::RecordSingleEvent(const base::char16* registry_path,
+                                   const base::char16* event_name) {
+  ExitFunnel funnel;
+
+  if (!funnel.Init(registry_path, base::GetCurrentProcessHandle()))
+    return false;
+
+  return funnel.RecordEvent(event_name);
+}
+
+}  // namespace browser_watcher