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

chrome/installer/launcher_support/chrome_launcher_support.cc

 // 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/installer/launcher_support/chrome_launcher_support.h"
 
 #include <windows.h>
 #include <tchar.h>
 #include "base/file_path.h"
 #include "base/file_util.h"
+#include "base/logging.h"
 #ifndef OFFICIAL_BUILD
 #include "base/path_service.h"
 #endif
 #include "base/string16.h"
 #include "base/win/registry.h"
 
 namespace {
 
-// TODO(erikwright): These constants are duplicated all over the place.
-// Consolidate them somehow.
+// http://crbug.com/148538
+// TODO(huangs) Refactor the constants:
+const wchar_t kChromeBinariesRegClientStateKey[] =
+    L"Software\\Google\\Update\\ClientState\\"
+    L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
 const wchar_t kChromeRegClientStateKey[] =
     L"Software\\Google\\Update\\ClientState\\"
     L"{8A69D345-D564-463c-AFF1-A69D9E530F96}";
 
 const wchar_t kUninstallStringField[] = L"UninstallString";
 
+// Copied from util_constants.cc.
 const wchar_t kChromeExe[] = L"chrome.exe";
 
 #ifndef OFFICIAL_BUILD
 FilePath GetDevelopmentChrome() {
   FilePath current_directory;
   if (PathService::Get(base::DIR_EXE, &current_directory)) {
     FilePath chrome_exe_path(current_directory.Append(kChromeExe));
     if (file_util::PathExists(chrome_exe_path))
       return chrome_exe_path;
   }
   return FilePath();
 }
 #endif
 
+// Looks for setup.exe from the registry field UninstallString from

[erikwright (departed), 2012/09/14 01:21:36]

nit: registry field -> value
"Reads the path to setup.exe from the value "UninstallString" within the
specified product's ClientState registry key. Returns an empty FilePath if an
error occurs or the product is not installed at the specified level."

[huangs, 2012/09/14 04:03:14]

Done. Have quotation around "ClientState", too.

+// the registry key of a specified product.
+FilePath GetSetupExeFromRegistry(HKEY root_key, const wchar_t* subkey) {
+  base::win::RegKey reg_key;
+  if (reg_key.Open(root_key, subkey, KEY_QUERY_VALUE) == ERROR_SUCCESS) {
+    string16 uninstall;
+    if (reg_key.ReadValue(kUninstallStringField, &uninstall) == ERROR_SUCCESS) {
+      FilePath setup_exe_path(uninstall);
+      if (file_util::PathExists(setup_exe_path))
+        return setup_exe_path;
+    }
+  }
+  return FilePath();
+}
+
 }  // namespace
 
 namespace chrome_launcher_support {
 
+FilePath GetSetupExeForInstallationLevel(InstallationLevel level) {
+  HKEY root_key = (level == USER_LEVEL_INSTALLATION ?

[erikwright (departed), 2012/09/14 01:21:36]

push this down into GetSetupExeFromRegistry (make InstallationLevel the first
parameter instead of HKEY).

[huangs, 2012/09/14 04:03:14]

Done.  Also wrapping "namespace chrome_launch_support" around anonymous
namespace to use InstallationLevel.

+                   HKEY_CURRENT_USER :
+                   HKEY_LOCAL_MACHINE);
+  FilePath setup_exe_path;

[erikwright (departed), 2012/09/14 01:21:36]

combine declaration and assignment.

[huangs, 2012/09/14 04:03:14]

Done.

+  // Look in the registry for Chrome Binaries first.
+  setup_exe_path =
+      GetSetupExeFromRegistry(root_key, kChromeBinariesRegClientStateKey);

[erikwright (departed), 2012/09/14 01:21:36]

Define constants for the app guids and pass those instead of the full registry
path.

Concatenate the registry path and app guids in GetSetupExeFromRegistry.

[huangs, 2012/09/14 04:03:14]

Done. Duplicating the GUID definitions in update.cc, to avoid introducing
externally visible strings that may conflict (we'll refactor this anyway).

+  // Faily the above, look in the registry for Chrome next.
+  if (setup_exe_path.empty()) {
+    setup_exe_path =
+        GetSetupExeFromRegistry(root_key, kChromeRegClientStateKey);
+  }
+  // May have failed, and then setup_exe_path would be empty.
+  return setup_exe_path;
+}
+
+FilePath GetChromePathForInstallationLevel(InstallationLevel level) {
+  FilePath setup_exe_path(GetSetupExeForInstallationLevel(level));
+  if (!setup_exe_path.empty()) {
+    FilePath chrome_exe_path;

[erikwright (departed), 2012/09/14 01:21:36]

combine declaration and assignment.

[huangs, 2012/09/14 04:03:14]

Done.

+    // The uninstall path contains the path to setup.exe which is two levels
+    // down from chrome.exe. Move up two levels (plus one to drop the file
+    // name) and look for chrome.exe from there.
+    chrome_exe_path =
+        setup_exe_path.DirName().DirName().DirName().Append(kChromeExe);
+    if (!file_util::PathExists(chrome_exe_path)) {
+      // By way of mild future proofing, look up one to see if there's a
+      // chrome.exe in the version directory
+      chrome_exe_path = chrome_exe_path.DirName().DirName().Append(kChromeExe);
+    }
+    if (file_util::PathExists(chrome_exe_path))
+      return chrome_exe_path;
+  }
+  return FilePath();
+}
+
 FilePath GetAnyChromePath() {
   FilePath chrome_path;
 #ifndef OFFICIAL_BUILD
   // For development mode, chrome.exe should be in same dir as the stub.
   chrome_path = GetDevelopmentChrome();
 #endif
   if (chrome_path.empty())
     chrome_path = GetChromePathForInstallationLevel(SYSTEM_LEVEL_INSTALLATION);
   if (chrome_path.empty())
     chrome_path = GetChromePathForInstallationLevel(USER_LEVEL_INSTALLATION);
-
   return chrome_path;
 }
 
-FilePath GetChromePathForInstallationLevel(InstallationLevel level) {
-  using base::win::RegKey;
-  HKEY root_key = (level == USER_LEVEL_INSTALLATION ?
-                   HKEY_CURRENT_USER :
-                   HKEY_LOCAL_MACHINE);
-  RegKey reg_key(root_key, kChromeRegClientStateKey, KEY_QUERY_VALUE);
-
-  FilePath chrome_exe_path;
-
-  if (reg_key.Valid()) {
-    // Now grab the uninstall string from the appropriate ClientState key
-    // and use that as the base for a path to chrome.exe.
-    string16 uninstall;
-    if (reg_key.ReadValue(kUninstallStringField, &uninstall) == ERROR_SUCCESS) {
-      // The uninstall path contains the path to setup.exe which is two levels
-      // down from chrome.exe. Move up two levels (plus one to drop the file
-      // name) and look for chrome.exe from there.
-      FilePath uninstall_path(uninstall);
-      chrome_exe_path =
-          uninstall_path.DirName().DirName().DirName().Append(kChromeExe);
-      if (!file_util::PathExists(chrome_exe_path)) {
-        // By way of mild future proofing, look up one to see if there's a
-        // chrome.exe in the version directory
-        chrome_exe_path =
-            uninstall_path.DirName().DirName().Append(kChromeExe);
-      }
-    }
-  }
-
-  if (file_util::PathExists(chrome_exe_path))
-    return chrome_exe_path;
-
-  return FilePath();
-}
-
 }  // namespace chrome_launcher_support