Import: DXF backend, frontent; add time measurement

src/Mod/Import/App/AppImportPy.cpp

@@ -48,6 +48,7 @@
 #endif
 #endif
 
+#include <chrono>
 #include "dxf/ImpExpDxf.h"
 #include "SketchExportHelper.h"
 #include <App/Application.h>
@@ -413,7 +414,13 @@ private:
             ImpExpDxfRead dxf_file(EncodedName, pcDoc);
             dxf_file.setOptionSource(defaultOptions);
             dxf_file.setOptions();
+
+            auto startTime = std::chrono::high_resolution_clock::now();
             dxf_file.DoRead(IgnoreErrors);
+            auto endTime = std::chrono::high_resolution_clock::now();
+            std::chrono::duration<double> elapsed = endTime - startTime;
+            dxf_file.setImportTime(elapsed.count());
+
             pcDoc->recompute();
             return dxf_file.getStatsAsPyObject();
         }
@@ -423,7 +430,6 @@ private:
         catch (const Base::Exception& e) {
             throw Py::RuntimeError(e.what());
         }
-        return Py::None();
     }