Removing the old Mac "root frame"

Doesn't seem to be needed anymore and may not have been for a long
time.

src/AudacityApp.cpp

@@ -252,8 +252,6 @@ static void wxOnAssert(const wxChar *fileName, int lineNumber, const wxChar *msg
 }
 #endif
 
-static wxFrame *gParentFrame = NULL;
-
 static bool gInited = false;
 bool gIsQuitting = false;
 
@@ -302,10 +300,6 @@ void QuitAudacity(bool bForce)
 
    ModuleManager::Get().Dispatch(AppQuiting);
 
-   if (gParentFrame)
-      gParentFrame->Destroy();
-   gParentFrame = NULL;
-
 #ifdef EXPERIMENTAL_SCOREALIGN
    CloseScoreAlignDialog();
 #endif
@@ -1416,10 +1410,6 @@ bool AudacityApp::OnInit()
    mRecentFiles->UseMenu(recentMenu);
    mRecentFiles->AddFilesToMenu(recentMenu);
 
-   // This invisibale frame will be the "root" of all other frames and will
-   // become the active frame when no projects are open.
-   gParentFrame = new wxFrame(NULL, -1, wxEmptyString, wxPoint(0, 0), wxSize(0, 0), 0);
-
 #endif //__WXMAC__
 
    SetExitOnFrameDelete(true);