map MenuToggleButton to GtkToggleButton with a custom menu property

we don't have non-menu ToggleButtons yet, so thats not done here.

since we first started with GtkPushButton:menu_attrib to indicate
menubuttons gtk has grown menu buttons, but they don't have the
idea of a gtktogglemenu button, so this attribute still has a role
to play I guess

Change-Id: Iebfe5ccf996e22784cf9aaf2bcf367eed79ae686
diff --git a/sfx2/uiconfig/ui/startcenter.ui b/sfx2/uiconfig/ui/startcenter.ui
index 68ab548..79b1484 100644
--- a/sfx2/uiconfig/ui/startcenter.ui
+++ b/sfx2/uiconfig/ui/startcenter.ui
@@ -171,7 +171,7 @@
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="open_recent:clearmenu">
                  <object class="GtkToggleButton" id="open_recent:clearmenu">
                    <property name="label" translatable="yes">_Recent Files</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
@@ -190,7 +190,7 @@
                  </packing>
                </child>
                <child>
                  <object class="GtkButton" id="templates_all:filtermenu">
                  <object class="GtkToggleButton" id="templates_all:filtermenu">
                    <property name="label" translatable="yes">T_emplates</property>
                    <property name="visible">True</property>
                    <property name="can_focus">True</property>
diff --git a/vcl/source/window/builder.cxx b/vcl/source/window/builder.cxx
index fc8069e..2f1fd3d 100644
--- a/vcl/source/window/builder.cxx
+++ b/vcl/source/window/builder.cxx
@@ -942,6 +942,22 @@ namespace
        return xWindow;
    }

    VclPtr<Button> extractStockAndBuildMenuToggleButton(vcl::Window *pParent, VclBuilder::stringmap &rMap)
    {
        WinBits nBits = WB_CLIPCHILDREN|WB_CENTER|WB_VCENTER|WB_3DLOOK;

        nBits |= extractRelief(rMap);

        VclPtr<Button> xWindow = VclPtr<MenuToggleButton>::Create(pParent, nBits);

        if (extractStock(rMap))
        {
            xWindow->SetText(getStockText(extractLabel(rMap)));
        }

        return xWindow;
    }

    OString extractUnit(const OString& sPattern)
    {
        OString sUnit(sPattern);
@@ -1370,6 +1386,17 @@ VclPtr<vcl::Window> VclBuilder::makeObject(vcl::Window *pParent, const OString &
        setupFromActionName(xButton, rMap, m_xFrame);
        xWindow = xButton;
    }
    else if (name == "GtkToggleButton")
    {
        VclPtr<Button> xButton;
        OString sMenu = extractCustomProperty(rMap);
        assert(sMenu.getLength() && "not implemented yet");
        xButton = extractStockAndBuildMenuToggleButton(pParent, rMap);
        m_pParserState->m_aButtonMenuMaps.push_back(ButtonMenuMap(id, sMenu));
        xButton->SetImageAlign(ImageAlign::Left); //default to left
        setupFromActionName(xButton, rMap, m_xFrame);
        xWindow = xButton;
    }
    else if (name == "GtkRadioButton")
    {
        extractGroup(id, rMap);