Make Application::SetDialogCancelMode "private"

Change callers to Application::EnableHeadlessMode instead except
for the Frame dispose sequence, which has to disable a fatal
mode temporary.

Since Frame is not a unique identifier, rename it to XFrameImpl,
otherwise we get a "non-unique" compile error for other files.

When we update our gcc baseline, we should be able to forward
declare and friend XFrameImpl and really make it private.

Change-Id: Ifcad0355adade8f6539ec092b174dd70af8352c2
Reviewed-on: https://gerrit.libreoffice.org/64050
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

include/vcl/svapp.hxx

@@ -1129,9 +1129,13 @@ public:
 
     /** Sets the dialog cancel mode for headless environments.
 
+     This should be private, but XFrameImpl needs to access it and current
+     baseline gcc doesn't support forward definition of anonymous classes.
+     You probably should use EnableHeadlessMode instead.
+
      @param     mode            DialogCancel mode value
 
-     @see GetDialogCancelMode, IsDialogCancelEnabled
+     @see GetDialogCancelMode, IsDialogCancelEnabled, EnableHeadlessMode
     */
     static void                 SetDialogCancelMode( DialogCancelMode mode );
 

vcl/workben/commonfuzzer.hxx

@@ -119,8 +119,8 @@ void CommonInitialize(int *argc, char ***argv)
         Application::Abort( "Failed to bootstrap" );
     comphelper::setProcessServiceFactory( xServiceManager );
     utl::ConfigManager::EnableFuzzing();
+    Application::EnableHeadlessMode(false);
     InitVCL();
-    Application::SetDialogCancelMode(DialogCancelMode::Silent);
 
     //we don't have a de-init, so inside this leak disabled region...
     //get the font info

vcl/workben/fftester.cxx

@@ -104,10 +104,9 @@ SAL_IMPLEMENT_MAIN_WITH_ARGS(argc, argv)
             createInstanceWithArguments("com.sun.star.ucb.FileContentProvider", aArgs), css::uno::UNO_QUERY_THROW);
         xUcb->registerContentProvider(xFileProvider, "file", true);
 
+        Application::EnableHeadlessMode(false);
         InitVCL();
 
-        Application::SetDialogCancelMode(DialogCancelMode::Silent);
-
         if (strcmp(argv[2], "wmf") == 0 || strcmp(argv[2], "emf") == 0)
         {
             GDIMetaFile aGDIMetaFile;