CFFL_FormFields only accept CPDFSDK_Widget subclass of CPDFSDK_Annot

So pass them as such. The end goal is fewer types from CPDFSDK that
CFFL needs to know about. In an ideal world, CPDFSDK_Widget might
implement some CFFL callback-interface that other annot classes
wouldn't.

Change-Id: I541f303fd3af600e78497fdcdc5e24c8a1c8beeb
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/85373
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_formfillenvironment.cpp b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
index 1822101..cfc71cb 100644
--- a/fpdfsdk/cpdfsdk_formfillenvironment.cpp
+++ b/fpdfsdk/cpdfsdk_formfillenvironment.cpp
@@ -125,7 +125,7 @@
   if (!pFormField)
     return;
 
-  auto* pPage = FPDFPageFromIPDFPage(pFormField->GetSDKAnnot()->GetPage());
+  auto* pPage = FPDFPageFromIPDFPage(pFormField->GetSDKWidget()->GetPage());
   DCHECK(pPage);
 
   CFX_PointF ptA = pFormField->PWLtoFFL(CFX_PointF(rect.left, rect.bottom));