Call RegDeleteKeyEx directly instead of via a wrapper.

This CL removed the old wrapper for RegDeleteKeyEx which was used for
compatibility with Windows XP. As the code base is only supported on
Windows 7 and above this function can be statically linked.

Bug: 986625
Change-Id: I46814d7758948c371de42f66a6e9e96e4a6bfb87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1714289Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: James Forshaw <forshaw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680128}

base/win/registry.cc

@@ -281,7 +281,7 @@ LONG RegKey::DeleteEmptyKey(const char16* name) {
     return result;
 
   if (count == 0)
-    return RegDeleteKeyExWrapper(key_, name, wow64access_, 0);
+    return RegDeleteKeyEx(key_, name, wow64access_, 0);
 
   return ERROR_DIR_NOT_EMPTY;
 }
@@ -430,29 +430,10 @@ bool RegKey::StartWatching(ChangeCallback callback) {
   return true;
 }
 
-// static
-LONG RegKey::RegDeleteKeyExWrapper(HKEY hKey,
-                                   const char16* lpSubKey,
-                                   REGSAM samDesired,
-                                   DWORD Reserved) {
-  typedef LSTATUS(WINAPI* RegDeleteKeyExPtr)(HKEY, LPCWSTR, REGSAM, DWORD);
-
-  RegDeleteKeyExPtr reg_delete_key_ex_func =
-      reinterpret_cast<RegDeleteKeyExPtr>(
-          GetProcAddress(GetModuleHandleA("advapi32.dll"), "RegDeleteKeyExW"));
-
-  if (reg_delete_key_ex_func)
-    return reg_delete_key_ex_func(hKey, as_wcstr(lpSubKey), samDesired,
-                                  Reserved);
-
-  // Windows XP does not support RegDeleteKeyEx, so fallback to RegDeleteKey.
-  return RegDeleteKey(hKey, as_wcstr(lpSubKey));
-}
-
 // static
 LONG RegKey::RegDelRecurse(HKEY root_key, const char16* name, REGSAM access) {
   // First, see if the key can be deleted without having to recurse.
-  LONG result = RegDeleteKeyExWrapper(root_key, name, access, 0);
+  LONG result = RegDeleteKeyEx(root_key, name, access, 0);
   if (result == ERROR_SUCCESS)
     return result;
 
@@ -497,7 +478,7 @@ LONG RegKey::RegDelRecurse(HKEY root_key, const char16* name, REGSAM access) {
   RegCloseKey(target_key);
 
   // Try again to delete the key.
-  result = RegDeleteKeyExWrapper(root_key, name, access, 0);
+  result = RegDeleteKeyEx(root_key, name, access, 0);
 
   return result;
 }

base/win/registry.h

@@ -142,13 +142,6 @@ class BASE_EXPORT RegKey {
  private:
   class Watcher;
 
-  // Calls RegDeleteKeyEx on supported platforms, alternatively falls back to
-  // RegDeleteKey.
-  static LONG RegDeleteKeyExWrapper(HKEY hKey,
-                                    const char16* lpSubKey,
-                                    REGSAM samDesired,
-                                    DWORD Reserved);
-
   // Recursively deletes a key and all of its subkeys.
   static LONG RegDelRecurse(HKEY root_key, const char16* name, REGSAM access);