Allow Registry Iterator functions to use a specified WOW64 mode when iterating.

chrome/browser/extensions/external_registry_loader_win.cc

Index: chrome/browser/extensions/external_registry_loader_win.cc
diff --git a/chrome/browser/extensions/external_registry_loader_win.cc b/chrome/browser/extensions/external_registry_loader_win.cc
index ce44ae75dcf4603b35de9c73dda36d0784505509..b6d083ee185d28b66350adcea993b39e4bff3bd4 100644
--- a/chrome/browser/extensions/external_registry_loader_win.cc
+++ b/chrome/browser/extensions/external_registry_loader_win.cc
@@ -68,11 +68,15 @@ void ExternalRegistryLoader::LoadOnFileThread() {
   // A map of IDs, to weed out duplicates between HKCU and HKLM.
   std::set<base::string16> keys;
   base::win::RegistryKeyIterator iterator_machine_key(
-      HKEY_LOCAL_MACHINE, base::ASCIIToWide(kRegistryExtensions).c_str());
+      HKEY_LOCAL_MACHINE,
+      base::ASCIIToWide(kRegistryExtensions).c_str(),
+      KEY_WOW64_32KEY);
   for (; iterator_machine_key.Valid(); ++iterator_machine_key)
     keys.insert(iterator_machine_key.Name());
   base::win::RegistryKeyIterator iterator_user_key(
-      HKEY_CURRENT_USER, base::ASCIIToWide(kRegistryExtensions).c_str());
+      HKEY_CURRENT_USER,
+      base::ASCIIToWide(kRegistryExtensions).c_str(),
+      0);

[Will Harris, 2014/10/07 02:03:16]

This could use the two parameter constructor but I think it makes it more
explicit that we're setting no WOW64 flags for the HKCU access.

[grt (UTC plus 2), 2014/10/07 15:47:10]

Why here and not everywhere that HKCU is used?

[Will Harris, 2014/10/07 17:16:14]

True, I'll change it back.

   for (; iterator_user_key.Valid(); ++iterator_user_key)
     keys.insert(iterator_user_key.Name());
 
@@ -86,7 +90,8 @@ void ExternalRegistryLoader::LoadOnFileThread() {
     key_path.append(L"\\");
     key_path.append(*it);
     if (key.Open(HKEY_LOCAL_MACHINE,

[grt (UTC plus 2), 2014/10/07 15:47:10]

nit:
    if (key.Open(...,
                 ...) != ERROR SUCCESS &&
        key.Open(...,
                 ...) != ERROR_SUCCESS) {
      LOG(ERROR) << ...;
      continue;
    }

[Will Harris, 2014/10/07 17:16:14]

Done.

-                 key_path.c_str(), KEY_READ) != ERROR_SUCCESS) {
+                 key_path.c_str(),
+                 KEY_READ | KEY_WOW64_32KEY) != ERROR_SUCCESS) {
       if (key.Open(HKEY_CURRENT_USER,
                    key_path.c_str(), KEY_READ) != ERROR_SUCCESS) {
         LOG(ERROR) << "Unable to read registry key at path (HKLM & HKCU): "