Make the outdated build detector disabler load and run on XP.

chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.cc

Index: chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.cc
diff --git a/chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.cc b/chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.cc
index 7c192399ac60b9e2462366cbcaa88e43bdd71a2f..919a8022b4ea8d2b010ed08af5780612d845fc05 100644
--- a/chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.cc
+++ b/chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.cc
@@ -4,48 +4,101 @@
 
 #include "chrome/tools/disable_outdated_build_detector/disable_outdated_build_detector.h"
 
-#include "base/command_line.h"
-#include "base/environment.h"
-#include "base/strings/string16.h"
-#include "base/win/registry.h"
+#include <stdlib.h>
+
+#include <algorithm>
+#include <string>
+
 #include "chrome/tools/disable_outdated_build_detector/google_update_integration.h"
 
 namespace {
 
+// A rudimentary switch finder that ignores prefixes (e.g., --, -, /).
+bool HasSwitch(const wchar_t* command_line, const wchar_t* a_switch) {
+  if (!command_line || !*command_line)
+    return false;
+  const wchar_t* line_end =
+      command_line + std::char_traits<wchar_t>::length(command_line);
+  const wchar_t* switch_end =
+      a_switch + std::char_traits<wchar_t>::length(a_switch);
+  return std::search(command_line, line_end, a_switch, switch_end) != line_end;
+}
+
+// Reads the value named |value_name| from a registry key into |value|. The
+// type in the registry is ignored. |value| is not modified in case of error.
+// presubmit: allow wstring
+uint32_t ReadString(HKEY key, const wchar_t* value_name, std::wstring* value) {
+  // Read the size of the value (in bytes).
+  uint32_t byte_length = 0;
+  uint32_t result = ::RegQueryValueEx(
+      key, value_name, nullptr /* lpReserved */, nullptr /* lpType */,
+      nullptr /* lpData */, reinterpret_cast<DWORD*>(&byte_length));
+  if (result != ERROR_SUCCESS)
+    return result;
+  if (!byte_length) {
+    value->resize(0);
+    return result;
+  }
+
+  // Handle odd sizes and missing string terminators.
+  size_t char_length = (byte_length + 3) / sizeof(wchar_t);
+  // presubmit: allow wstring
+  std::wstring buffer(char_length, L'\0');
+
+  byte_length = static_cast<uint32_t>(char_length * sizeof(wchar_t));
+  result = ::RegQueryValueEx(key, value_name, nullptr /* lpReserved */,
+                             nullptr /* lpType */,
+                             reinterpret_cast<uint8_t*>(&buffer[0]),
+                             reinterpret_cast<DWORD*>(&byte_length));
+  if (result != ERROR_SUCCESS)
+    return result;
+  if (!byte_length) {
+    value->resize(0);
+    return result;
+  }
+
+  // Shrink the string to chop off the terminator.
+  if (!buffer[(byte_length - 1) / sizeof(wchar_t)])
+    buffer.resize((byte_length - 1) / sizeof(wchar_t));
+  else
+    buffer.resize((byte_length + 1) / sizeof(wchar_t));
+
+  value->swap(buffer);
+  return result;
+}
+
 // Returns true if the tool is to operate on a system-level Chrome on the basis
 // of either the --system-level command line switch or the GoogleUpdateIsMachine
 // environment variable.
-bool IsSystemLevel(const base::CommandLine& command_line) {
-  if (command_line.HasSwitch(switches::kSystemLevel))
+bool IsSystemLevel(const wchar_t* command_line) {
+  if (HasSwitch(command_line, switches::kSystemLevel))
     return true;
 
-  std::string is_machine;
-  return base::Environment::Create()->GetVar(env::kGoogleUpdateIsMachine,
-                                             &is_machine) &&
-         is_machine.size() == 1 && is_machine[0] == '1';
+  wchar_t buffer[2] = {};
+  return ::GetEnvironmentVariableW(env::kGoogleUpdateIsMachine, &buffer[0],
+                                   static_cast<DWORD>(_countof(buffer))) == 1 &&
+         buffer[0] == L'1';
 }
 
 // Returns true if Chrome is multi-install.
 bool IsChromeMultiInstall(bool system_level) {
-  base::win::RegKey key;
+  HKEY key = nullptr;
 
   LONG result = OpenClientStateKey(system_level, App::CHROME_BROWSER, &key);
   if (result != ERROR_SUCCESS)
     return false;
-  base::string16 uninstall_arguments;
-  result = key.ReadValue(kUninstallArguments, &uninstall_arguments);
-  if (result != ERROR_SUCCESS)
-    return false;
-  base::CommandLine command_line =
-      base::CommandLine::FromString(L"\"foo\" " + uninstall_arguments);
-  return command_line.HasSwitch(switches::kMultiInstall);
+  // presubmit: allow wstring
+  std::wstring uninstall_arguments;
+  ReadString(key, kUninstallArguments, &uninstall_arguments);
+  ::RegCloseKey(key);
+  return HasSwitch(uninstall_arguments.c_str(), switches::kMultiInstall);
 }
 
 // Disables the outdated build detector for |app|. On failures, |detail| will be
 // populated with a Windows error code corresponding to the failure mode.
 // Returns the exit code for the operation.
 ExitCode DisableForApp(bool system_level, App app, uint32_t* detail) {
-  base::win::RegKey key;
+  HKEY key = nullptr;
 
   *detail = OpenClientStateKey(system_level, app, &key);
   if (*detail == ERROR_FILE_NOT_FOUND)
@@ -53,19 +106,25 @@ ExitCode DisableForApp(bool system_level, App app, uint32_t* detail) {
   if (*detail != ERROR_SUCCESS)
     return ExitCode::FAILED_OPENING_KEY;
 
-  base::string16 brand;
-  *detail = key.ReadValue(kBrand, &brand);
-  if (*detail != ERROR_SUCCESS && *detail != ERROR_FILE_NOT_FOUND)
-    return ExitCode::FAILED_READING_BRAND;
-
-  if (!IsOrganic(brand))
-    return ExitCode::NON_ORGANIC_BRAND;
-
-  *detail = key.WriteValue(kBrand, kAOHY);
-  if (*detail != ERROR_SUCCESS)
-    return ExitCode::FAILED_WRITING_BRAND;
+  ExitCode exit_code = ExitCode::UNKNOWN_FAILURE;
+  // presubmit: allow wstring
+  std::wstring brand;
+  *detail = ReadString(key, kBrand, &brand);
+  if (*detail != ERROR_SUCCESS && *detail != ERROR_FILE_NOT_FOUND) {
+    exit_code = ExitCode::FAILED_READING_BRAND;
+  } else if (!IsOrganic(brand)) {
+    exit_code = ExitCode::NON_ORGANIC_BRAND;
+  } else {
+    *detail = ::RegSetValueEx(
+        key, kBrand, 0 /* Reserved */, REG_SZ,
+        reinterpret_cast<const uint8_t*>(&kAOHY[0]),
+        (std::char_traits<wchar_t>::length(kAOHY) + 1) * sizeof(wchar_t));
+    exit_code = *detail == ERROR_SUCCESS ? ExitCode::CHROME_BRAND_UPDATED
+                                         : ExitCode::FAILED_WRITING_BRAND;
+  }
+  ::RegCloseKey(key);
 
-  return ExitCode::CHROME_BRAND_UPDATED;
+  return exit_code;
 }
 
 // Disables the outdated build detector for organic installs of Chrome by
@@ -92,7 +151,7 @@ ExitCode DisableOutdatedBuildDetectorImpl(bool system_level, uint32_t* detail) {
 
 }  // namespace
 
-ExitCode DisableOutdatedBuildDetector(const base::CommandLine& command_line) {
+ExitCode DisableOutdatedBuildDetector(const wchar_t* command_line) {
   const bool system_level = IsSystemLevel(command_line);
   ResultInfo result_info = {
       InstallerResult::FAILED_CUSTOM_ERROR,  // installer_result