Qt5 don't assert broken height or width

At least maths element docking window has a floating height of zero.
So the original gtk comment about broken values is still true.

And the initial SalFrameGeometry is ok, so no need to initialize it.
And set default size and position on show, if not explicitly set.

Reviewed-on: https://gerrit.libreoffice.org/74614
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
(cherry picked from commit bbbc820d7920a31669cb7e9aaeb5beb072eae175)

Change-Id: Ibe4969a164b50b666745ce010f5100af4b3ff2f6
Reviewed-on: https://gerrit.libreoffice.org/74623
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
diff --git a/vcl/inc/qt5/Qt5Frame.hxx b/vcl/inc/qt5/Qt5Frame.hxx
index 5b1bc10..4c94b84 100644
--- a/vcl/inc/qt5/Qt5Frame.hxx
+++ b/vcl/inc/qt5/Qt5Frame.hxx
@@ -109,7 +109,7 @@ class VCLPLUG_QT5_PUBLIC Qt5Frame : public QObject, public SalFrame
    ScreenSaverInhibitor m_ScreenSaverInhibitor;
#endif

    void Center();
    void SetDefaultPos();
    Size CalcDefaultSize();
    void SetDefaultSize();

diff --git a/vcl/qt5/Qt5Frame.cxx b/vcl/qt5/Qt5Frame.cxx
index 20cb448..da3dc66 100644
--- a/vcl/qt5/Qt5Frame.cxx
+++ b/vcl/qt5/Qt5Frame.cxx
@@ -163,21 +163,6 @@ Qt5Frame::Qt5Frame(Qt5Frame* pParent, SalFrameStyleFlags nStyle, bool bUseCairo)
            pChildWindow->setTransientParent(pParentWindow);
    }

    // fake an initial geometry, gets updated via configure event or SetPosSize
    if (m_bDefaultPos || m_bDefaultSize)
    {
        maGeometry.nDisplayScreenNumber = 0;
        Size aDefSize = CalcDefaultSize();
        maGeometry.nX = 0;
        maGeometry.nY = 0;
        maGeometry.nWidth = aDefSize.Width();
        maGeometry.nHeight = aDefSize.Height();
        maGeometry.nTopDecoration = 0;
        maGeometry.nBottomDecoration = 0;
        maGeometry.nLeftDecoration = 0;
        maGeometry.nRightDecoration = 0;
    }

    m_aSystemData.nSize = sizeof(SystemEnvData);

    // Calling 'QWidget::winId()' implicitly enables native windows to be used
@@ -370,6 +355,7 @@ void Qt5Frame::Show(bool bVisible, bool /*bNoActivate*/)
    assert(m_pQWidget);

    SetDefaultSize();
    SetDefaultPos();

    auto* pSalInst(static_cast<Qt5Instance*>(GetSalData()->m_pInstance));
    assert(pSalInst);
@@ -388,15 +374,22 @@ void Qt5Frame::SetMaxClientSize(long nWidth, long nHeight)
        asChild()->setMaximumSize(nWidth, nHeight);
}

void Qt5Frame::Center()
void Qt5Frame::SetDefaultPos()
{
    if (!m_bDefaultPos)
        return;

    // center on parent
    if (m_pParent)
    {
        QWidget* pWindow = m_pParent->GetQWidget()->window();
        QWidget* const pWindow = m_pParent->GetQWidget()->window();
        QWidget* const pWidget = asChild();
        pWidget->move(pWindow->frameGeometry().topLeft() + pWindow->rect().center()
                      - pWidget->rect().center());
        QPoint aPos = pWindow->rect().center() - pWidget->rect().center();
        SetPosSize(aPos.x(), aPos.y(), 0, 0, SAL_FRAME_POSSIZE_X | SAL_FRAME_POSSIZE_Y);
        assert(!m_bDefaultPos);
    }
    else
        m_bDefaultPos = false;
}

Size Qt5Frame::CalcDefaultSize()
@@ -443,31 +436,30 @@ void Qt5Frame::SetPosSize(long nX, long nY, long nWidth, long nHeight, sal_uInt1

    if (nFlags & (SAL_FRAME_POSSIZE_WIDTH | SAL_FRAME_POSSIZE_HEIGHT))
    {
        m_bDefaultSize = false;
        if (isChild(false) || !m_pQWidget->isMaximized())
        {
            if (!(nFlags & SAL_FRAME_POSSIZE_WIDTH))
                nWidth = maGeometry.nWidth;
            else if (!(nFlags & SAL_FRAME_POSSIZE_HEIGHT))
                nHeight = maGeometry.nHeight;
            assert(nWidth > 0 && nHeight > 0);

            if (nWidth > 0 && nHeight > 0)
            {
                m_bDefaultSize = false;
                if (m_nStyle & SalFrameStyleFlags::SIZEABLE)
                    asChild()->resize(nWidth, nHeight);
                else
                    asChild()->setFixedSize(nWidth, nHeight);

                // assume the resize happened
                // needed for calculations and will eventuall be corrected by events
                maGeometry.nWidth = nWidth;
                maGeometry.nHeight = nHeight;
            }

            // assume the resize happened
            // needed for calculations and will eventually be corrected by events
            if (nWidth > 0)
                maGeometry.nWidth = nWidth;
            if (nHeight > 0)
                maGeometry.nHeight = nHeight;
        }
    }
    else
        SetDefaultSize();

    if (nFlags & (SAL_FRAME_POSSIZE_X | SAL_FRAME_POSSIZE_Y))
    {
@@ -498,10 +490,6 @@ void Qt5Frame::SetPosSize(long nX, long nY, long nWidth, long nHeight, sal_uInt1
        m_bDefaultPos = false;
        asChild()->move(nX, nY);
    }
    else if (m_bDefaultPos)
        Center();

    m_bDefaultPos = false;
}

void Qt5Frame::GetClientSize(long& rWidth, long& rHeight)