Refactor code finding the name of the windows class to use in wxMSW

Determine which class name to use in MSWCreate() caller instead of doing it
partly there and partly in MSWCreate() itself, which used to add the "NR"
suffix if necessary -- now it doesn't do this any more and just really created
the window using the given class.

No real changes, just prepare for future enhancements.

src/msw/app.cpp

@@ -112,6 +112,13 @@ struct ClassRegInfo
     {
     }
 
+    // Return the appropriate string depending on the presence of
+    // RegClass_ReturnNR bit in the flags.
+    const wxChar* GetRequestedName(int flags) const
+    {
+        return (flags & wxApp::RegClass_ReturnNR ? regnameNR : regname).t_str();
+    }
+
     // the name of the registered class with and without CS_[HV]REDRAW styles
     wxString regname;
     wxString regnameNR;
@@ -630,13 +637,14 @@ bool wxApp::Initialize(int& argc_, wxChar **argv_)
 /* static */
 const wxChar *wxApp::GetRegisteredClassName(const wxChar *name,
                                             int bgBrushCol,
-                                            int extraStyles)
+                                            int extraStyles,
+                                            int flags)
 {
     const size_t count = gs_regClassesInfo.size();
     for ( size_t n = 0; n < count; n++ )
     {
         if ( gs_regClassesInfo[n].regname == name )
-            return gs_regClassesInfo[n].regname.c_str();
+            return gs_regClassesInfo[n].GetRequestedName(flags);
     }
 
     // we need to register this class
@@ -675,7 +683,7 @@ const wxChar *wxApp::GetRegisteredClassName(const wxChar *name,
     // function returns (it could be invalidated later if new elements are
     // added to the vector and it's reallocated but this shouldn't matter as
     // this pointer should be used right now, not stored)
-    return gs_regClassesInfo.back().regname.t_str();
+    return gs_regClassesInfo.back().GetRequestedName(flags);
 }
 
 bool wxApp::IsRegisteredClassName(const wxString& name)