Add vcl::Window::SetLastMousePos()

This is needed, as e.g. sd::FuText::DoExecute() queries the mouse
position from VCL, which won't be correct in case the mouse event is
generated by a LOK client, not by VCL. So add a method that makes it
possible to set the position before MouseButton*() starts.

Change-Id: I1e24ffb2a4a866c9cac89367907ffaec336ad1f6

include/vcl/window.hxx

@@ -1013,6 +1013,8 @@ public:
     void                                SetPointerPosPixel( const Point& rPos );
     Point                               GetPointerPosPixel();
     Point                               GetLastPointerPosPixel();
+    /// Similar to SetPointerPosPixel(), but sets the frame data's last mouse position instead.
+    void                                SetLastMousePos(const Point& rPos);
     void                                ShowPointer( bool bVisible );
     void                                EnterWait();
     void                                LeaveWait();

vcl/source/window/mouse.cxx

@@ -532,6 +532,15 @@ void Window::SetPointerPosPixel( const Point& rPos )
     mpWindowImpl->mpFrame->SetPointerPos( aPos.X(), aPos.Y() );
 }
 
+void Window::SetLastMousePos(const Point& rPos)
+{
+    // Do this conversion, so when GetPointerPosPixel() calls
+    // ImplFrameToOutput(), we get back the original position.
+    Point aPos = ImplOutputToFrame(rPos);
+    mpWindowImpl->mpFrameData->mnLastMouseX = aPos.X();
+    mpWindowImpl->mpFrameData->mnLastMouseY = aPos.Y();
+}
+
 Point Window::GetPointerPosPixel()
 {