shdocvw: Add basic support for InPlaceDeactivate.

dlls/shdocvw/oleobject.c

@@ -623,7 +623,13 @@ static HRESULT WINAPI OleInPlaceObject_InPlaceDeactivate(IOleInPlaceObject *ifac
 {
     WebBrowser *This = INPLACEOBJ_THIS(iface);
     FIXME("(%p)\n", This);
-    return E_NOTIMPL;
+
+    if(This->inplace) {
+        IOleInPlaceSite_Release(This->inplace);
+        This->inplace = NULL;
+    }
+
+    return S_OK;
 }
 
 static HRESULT WINAPI OleInPlaceObject_UIDeactivate(IOleInPlaceObject *iface)