If Chrome Binaries version > App Host version, then update App Host.

chrome/browser/extensions/app_host/app_host_upgrade.cc

Index: chrome/browser/extensions/app_host/app_host_upgrade.cc
diff --git a/chrome/browser/extensions/app_host/app_host_upgrade.cc b/chrome/browser/extensions/app_host/app_host_upgrade.cc
new file mode 100755
index 0000000000000000000000000000000000000000..21c062108da015557aa089f3737f3d6b71c73d07
--- /dev/null
+++ b/chrome/browser/extensions/app_host/app_host_upgrade.cc
@@ -0,0 +1,78 @@
+// 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 "chrome/browser/extensions/app_host/app_host_upgrade.h"
+#include "chrome/installer/launcher_support/chrome_launcher_support.h"

[erikwright (departed), 2012/09/13 01:13:44]

chrome_launcher_support should be ordered with the other includes below.

[huangs, 2012/09/13 04:40:47]

Done.

+
+#include <windows.h>
+#include <tchar.h>

[erikwright (departed), 2012/09/13 01:13:44]

what is tchar used for?

[huangs, 2012/09/13 04:40:47]

I mistakenly thought it was needed for wchar_t.  Deleted.

+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/process_util.h"
+#include "base/string16.h"
+#include "base/string_util.h"
+#include "base/version.h"
+#include "base/win/registry.h"
+
+namespace app_host {
+
+const wchar_t kGoogleRegClientsKey[] =

[erikwright (departed), 2012/09/13 01:13:44]

anonymous namespace for this and other constants not used outside this file.

[huangs, 2012/09/13 04:40:47]

Done.

+    L"Software\\Google\\Update\\Clients\\";
+
+// Copied from chrome_appid.cc
+const wchar_t kMultiInstallAppGuid[] =
+    L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
+const wchar_t kChromeAppHostAppGuid[] =
+    L"{FDA71E6F-AC4C-4a00-8B70-9958A68906BF}";
+
+// Copied from util_constants.cc
+const char kMultiInstall[] = "multi-install";
+const char kChromeAppHost[] = "app-host";
+const char kVerboseLogging[] = "verbose-logging";
+
+// Copied from google_update_constants.cc
+const wchar_t kRegVersionField[] = L"pv";
+
+// TODO(huangs): Refactor parameter |system_level|.

[erikwright (departed), 2012/09/13 01:13:44]

TODO unnecessary.

[huangs, 2012/09/13 04:40:47]

Done.

+bool GetAppVersionForInstallationLevel(const wchar_t* app_guid,
+                                       bool system_level,
+                                       Version* version) {
+  using base::win::RegKey;

[erikwright (departed), 2012/09/13 01:13:44]

This is only used once, right? So 'using' is overkill.

[huangs, 2012/09/13 04:40:47]

Done.

+  HKEY root_key = system_level ? HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
+  string16 client_key(kGoogleRegClientsKey);
+  client_key.append(app_guid);
+  LOG(INFO) << "Trying to get " << client_key;

[erikwright (departed), 2012/09/13 01:13:44]

remove log statement.

[huangs, 2012/09/13 04:40:47]

Done.

+  RegKey reg_key;
+  string16 version_str;
+  if ((reg_key.Open(root_key, client_key.c_str(), KEY_QUERY_VALUE)
+      != ERROR_SUCCESS) ||

[erikwright (departed), 2012/09/13 01:13:44]

!= should go on previous line (prefer wrap after operator)

[huangs, 2012/09/13 04:40:47]

Done.

+      (reg_key.ReadValue(kRegVersionField, &version_str) != ERROR_SUCCESS)) {
+    return false;
+  }
+  *version = Version(WideToASCII(version_str));
+  return version->IsValid();
+}
+
+// TODO(huangs): Refactor parameter |system_level|.

[erikwright (departed), 2012/09/13 01:13:44]

remove TODO

[huangs, 2012/09/13 04:40:47]

Done.

+bool UpgradeAppHost(bool system_level) {
+  using namespace chrome_launcher_support;
+  // Get the path to the setup.exe.
+  FilePath setup_exe(GetSetupExeForInstallationLevel(
+      system_level ? SYSTEM_LEVEL_INSTALLATION : USER_LEVEL_INSTALLATION));
+  if (setup_exe.empty()) {
+    LOG(INFO) << "Failed to find setup.exe";
+    return false;
+  }
+  CommandLine cmd_line(setup_exe);
+  cmd_line.AppendSwitch(kMultiInstall);
+  cmd_line.AppendSwitch(kChromeAppHost);
+  if (CommandLine::ForCurrentProcess()->HasSwitch(

[erikwright (departed), 2012/09/13 01:13:44]

Don't check the command-line for the current process. For now, always add
kVerboseLogging but add a TODO to only add it if it's present in the setup
arguments for the system-level chrome binaries.

[huangs, 2012/09/13 04:40:47]

Done.

+      kVerboseLogging)) {
+    cmd_line.AppendSwitch(kVerboseLogging);
+  }
+  LOG(INFO) << "Command line: " << cmd_line.GetCommandLineString();

[erikwright (departed), 2012/09/13 01:13:44]

"Upgrading app_host.exe using command-line: ..."

[huangs, 2012/09/13 04:40:47]

Done.

+  return base::LaunchProcess(cmd_line, base::LaunchOptions(), NULL);
+}
+
+}  // namespace app_host