Use UnownedPtr<> in CXFA_RenderContext.

Change-Id: I0658f63a0d8fb8a5233e135dacedc4153532f01d
Reviewed-on: https://pdfium-review.googlesource.com/41112
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/xfa/fxfa/cxfa_rendercontext.h b/xfa/fxfa/cxfa_rendercontext.h
index 411830d..9338494 100644
--- a/xfa/fxfa/cxfa_rendercontext.h
+++ b/xfa/fxfa/cxfa_rendercontext.h
@@ -9,6 +9,7 @@
 
 #include <memory>
 
+#include "core/fxcrt/unowned_ptr.h"
 #include "xfa/fxfa/fxfa.h"
 
 class CXFA_Graphics;
@@ -24,7 +25,7 @@
 
  private:
   std::unique_ptr<IXFA_WidgetIterator> m_pWidgetIterator;
-  CXFA_FFWidget* m_pWidget;
+  UnownedPtr<CXFA_FFWidget> m_pWidget;
   CFX_Matrix m_matrix;
   CFX_RectF m_rtClipRect;
 };