Windows sbox: Warmup locales before sandbox lockdown (and tests)

sandbox/win/src/target_services.cc

Index: sandbox/win/src/target_services.cc
diff --git a/sandbox/win/src/target_services.cc b/sandbox/win/src/target_services.cc
index 116f0c929b81ee71ac9d5f7f686593e56a3e78f4..fd16b9ea002d9fc73489cdc4ded5eec5df4ecc46 100644
--- a/sandbox/win/src/target_services.cc
+++ b/sandbox/win/src/target_services.cc
@@ -59,6 +59,22 @@ bool CloseOpenHandles(bool* is_csrss_connected) {
   return true;
 }
 
+// Warm up language subsystems before the sandbox is turned on.
+// Tested on Win8.1 x64:
+// This needs to happen after RevertToSelf() is called, because (at least) in
+// the case of GetUserDefaultLCID() it checks the TEB to see if the process is
+// impersonating (TEB!IsImpersonating). If it is, the cached locale information
+// is not used, nor is it set. Therefore, calls after RevertToSelf() will not
+// have warmed-up values to use.
+bool WarmupWindowsLocales() {
+  // NOTE(liamjm): When last checked (Win 8.1 x64) it wasn't necessary to
+  // warmup all of these functions, but let's not assume that.
+  ::GetUserDefaultLangID();
+  ::GetUserDefaultLCID();
+  wchar_t localeName[LOCALE_NAME_MAX_LENGTH] = { 0 };
+  return (0 != ::GetUserDefaultLocaleName(
+      localeName, LOCALE_NAME_MAX_LENGTH * sizeof(wchar_t)));
+}
 
 // Used as storage for g_target_services, because other allocation facilities
 // are not available early. We can't use a regular function static because on
@@ -97,6 +113,8 @@ void TargetServicesBase::LowerToken() {
     ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_FLUSHANDLES);
   if (ERROR_SUCCESS != ::RegDisablePredefinedCache())
     ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_CACHEDISABLE);
+  if (!WarmupWindowsLocales())
+      ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_WARMUP);
   bool is_csrss_connected = true;
   if (!CloseOpenHandles(&is_csrss_connected))
     ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_CLOSEHANDLES);