tdf#102688: prevent leaking of VirtualDevice instances.

Change-Id: I6fb8e5b7fc5c0cef8f7ab1f93f5096ad588d57c7
Reviewed-on: https://gerrit.libreoffice.org/33601Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>

editeng/source/editeng/impedit.hxx

@@ -420,6 +420,7 @@ private:
 
     VclPtr< VirtualDevice> pVirtDev;
     VclPtr< OutputDevice > pRefDev;
+    VclPtr<VirtualDevice> mpOwnDev;
 
     svtools::ColorConfig*   pColorConfig;
     mutable SvtCTLOptions*  pCTLOptions;

editeng/source/editeng/impedit2.cxx

@@ -176,6 +176,7 @@ ImpEditEngine::~ImpEditEngine()
     bDowning = true;
     SetUpdateMode( false );
 
+    mpOwnDev.disposeAndClear();
     pVirtDev.disposeAndClear();
     delete pEmptyItemSet;
     delete pUndoManager;
@@ -207,7 +208,8 @@ void ImpEditEngine::SetRefMapMode( const MapMode& rMapMode )
     if ( GetRefDevice()->GetMapMode() == rMapMode )
         return;
 
-    pRefDev = VclPtr<VirtualDevice>::Create();
+    mpOwnDev = VclPtr<VirtualDevice>::Create();
+    pRefDev = mpOwnDev;
     pRefDev->SetMapMode( MapUnit::MapTwip );
     SetRefDevice( pRefDev );