Avoid string comparison if result is known

Change-Id: I766c343194f81497f95108d1259b697d3ad363a5
Reviewed-on: https://gerrit.libreoffice.org/67642
Tested-by: Jenkins
Reviewed-by: Matteo Casalin <matteo.casalin@yahoo.com>

sd/source/ui/view/viewshel.cxx

@@ -541,7 +541,7 @@ OString ViewShell::GetTextSelection(const OString& _aMimeType, OString& rUsedMim
 
     datatransfer::DataFlavor aFlavor;
     aFlavor.MimeType = OUString::fromUtf8(aMimeType.getStr());
-    if (aMimeType == "text/plain;charset=utf-16")
+    if (bConvert || aMimeType == "text/plain;charset=utf-16")
         aFlavor.DataType = cppu::UnoType<OUString>::get();
     else
         aFlavor.DataType = cppu::UnoType< uno::Sequence<sal_Int8> >::get();