Destroy window before cleaning up combobox

fpdfsdk/formfiller/cffl_combobox.cpp

Index: fpdfsdk/formfiller/cffl_combobox.cpp
diff --git a/fpdfsdk/formfiller/cffl_combobox.cpp b/fpdfsdk/formfiller/cffl_combobox.cpp
index 35591cff74215cf68a46fbcf02c187925b7214da..f6aef20c02e42e333dfb9d14d2b51f92719ce18f 100644
--- a/fpdfsdk/formfiller/cffl_combobox.cpp
+++ b/fpdfsdk/formfiller/cffl_combobox.cpp
@@ -24,6 +24,11 @@ CFFL_ComboBox::CFFL_ComboBox(CPDFDoc_Environment* pApp, CPDFSDK_Annot* pAnnot)
 CFFL_ComboBox::~CFFL_ComboBox() {
   for (const auto& it : m_Maps)
     it.second->InvalidateFocusHandler(this);
+
+  // See comment in cffl_formfiller.h.
+  // The font map should be stored somewhere more appropriate so it will live
+  // until the PWL_Edit is done with it. pdfium:566
+  DestroyWindows();
   delete m_pFontMap;
 }