Reverse order of CPWL_ListCtrl and CPWL_List_Notify cleanup

(Speculative) fix for the crash in 1137630, since it only reproduces
sporadically on my system, but hasn't re-occured since applying the
patch.

Bug: chromium:1137630
Change-Id: I4f52c7109eca00dfa8faee9bc6341cd94c25b60c
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/75090
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

fpdfsdk/pwl/cpwl_list_box.h

diff --git a/fpdfsdk/pwl/cpwl_list_box.h b/fpdfsdk/pwl/cpwl_list_box.h
index 48b53e5..1e56697 100644
--- a/fpdfsdk/pwl/cpwl_list_box.h
+++ b/fpdfsdk/pwl/cpwl_list_box.h
@@ -97,8 +97,8 @@
  protected:
   bool m_bMouseDown = false;
   bool m_bHoverSel = false;
+  std::unique_ptr<CPWL_List_Notify> m_pListNotify;  // Must outlive |m_pList|.
   std::unique_ptr<CPWL_ListCtrl> m_pList;
-  std::unique_ptr<CPWL_List_Notify> m_pListNotify;
   UnownedPtr<IPWL_Filler_Notify> m_pFillerNotify;
 
  private: