callcatcher: remove unused SystemChildWindow::IsEraseBackgroundEnabled

vcl/inc/vcl/syschild.hxx

@@ -63,7 +63,6 @@ public:
     //  per default systemchildwindows erase their background for better plugin support
     //  however, this might not always be required
     void                    EnableEraseBackground( sal_Bool bEnable = sal_True );
-    sal_Bool                IsEraseBackgroundEnabled();
     void                    SetForwardKey( sal_Bool bEnable );
     // return the platform specific handle/id of this window;
     // in case the flag bUseJava is set, a java compatible overlay window

vcl/source/window/syschild.cxx

@@ -198,16 +198,6 @@ void SystemChildWindow::EnableEraseBackground( sal_Bool bEnable )
 
 // -----------------------------------------------------------------------
 
-sal_Bool SystemChildWindow::IsEraseBackgroundEnabled()
-{
-    if ( mpWindowImpl->mpSysObj )
-        return mpWindowImpl->mpSysObj->IsEraseBackgroundEnabled();
-    else
-        return sal_False;
-}
-
-// -----------------------------------------------------------------------
-
 void SystemChildWindow::ImplTestJavaException( void* pEnv )
 {
 #ifdef SOLAR_JAVA