win32u: Introduce and use new reg_(open|create)_ascii_key helpers.

dlls/win32u/font.c

@@ -516,6 +516,12 @@ HKEY reg_open_key( HKEY root, const WCHAR *name, ULONG name_len )
     return ret;
 }
 
+HKEY reg_open_ascii_key( HKEY root, const char *name )
+{
+    WCHAR nameW[MAX_PATH];
+    return reg_open_key( root, nameW, asciiz_to_unicode( nameW, name ) - sizeof(WCHAR) );
+}
+
 /* wrapper for NtCreateKey that creates the key recursively if necessary */
 HKEY reg_create_key( HKEY root, const WCHAR *name, ULONG name_len,
                      DWORD options, DWORD *disposition )
@@ -565,10 +571,17 @@ HKEY reg_create_key( HKEY root, const WCHAR *name, ULONG name_len,
     return ret;
 }
 
+HKEY reg_create_ascii_key( HKEY root, const char *name, DWORD options,
+                           DWORD *disposition )
+{
+    WCHAR nameW[MAX_PATH];
+    return reg_create_key( root, nameW, asciiz_to_unicode( nameW, name ) - sizeof(WCHAR),
+                           options, disposition );
+}
+
 HKEY reg_open_hkcu_key( const char *name )
 {
-    WCHAR nameW[128];
-    return reg_open_key( hkcu_key, nameW, asciiz_to_unicode( nameW, name ) - sizeof(WCHAR) );
+    return reg_open_ascii_key( hkcu_key, name );
 }
 
 BOOL set_reg_value( HKEY hkey, const WCHAR *name, UINT type, const void *value, DWORD count )

dlls/win32u/win32u_private.h

@@ -260,8 +260,11 @@ extern int muldiv( int a, int b, int c );
 
 extern HKEY reg_create_key( HKEY root, const WCHAR *name, ULONG name_len,
                             DWORD options, DWORD *disposition );
+extern HKEY reg_create_ascii_key( HKEY root, const char *name, DWORD options,
+                                  DWORD *disposition );
 extern HKEY reg_open_hkcu_key( const char *name );
 extern HKEY reg_open_key( HKEY root, const WCHAR *name, ULONG name_len );
+extern HKEY reg_open_ascii_key( HKEY root, const char *name );
 extern ULONG query_reg_value( HKEY hkey, const WCHAR *name,
                               KEY_VALUE_PARTIAL_INFORMATION *info, ULONG size );
 extern ULONG query_reg_ascii_value( HKEY hkey, const char *name,