Clean up CPDF_AnnotList.

fpdfsdk/include/fsdk_mgr.h

Index: fpdfsdk/include/fsdk_mgr.h
diff --git a/fpdfsdk/include/fsdk_mgr.h b/fpdfsdk/include/fsdk_mgr.h
index 2c063ed5a8c434af9a98e2874562ddf05fbf4d00..b788f7d6054ceb1cc8ebf86df4deb3e7790ce8dc 100644
--- a/fpdfsdk/include/fsdk_mgr.h
+++ b/fpdfsdk/include/fsdk_mgr.h
@@ -291,9 +291,9 @@ class CPDFSDK_PageView final {
   void PageView_OnDraw(CFX_RenderDevice* pDevice,
                        CPDF_Matrix* pUser2Device,
                        CPDF_RenderOptions* pOptions);
-  CPDF_Annot* GetPDFAnnotAtPoint(FX_FLOAT pageX, FX_FLOAT pageY);
+  const CPDF_Annot* GetPDFAnnotAtPoint(FX_FLOAT pageX, FX_FLOAT pageY);
   CPDFSDK_Annot* GetFXAnnotAtPoint(FX_FLOAT pageX, FX_FLOAT pageY);
-  CPDF_Annot* GetPDFWidgetAtPoint(FX_FLOAT pageX, FX_FLOAT pageY);
+  const CPDF_Annot* GetPDFWidgetAtPoint(FX_FLOAT pageX, FX_FLOAT pageY);
   CPDFSDK_Annot* GetFXWidgetAtPoint(FX_FLOAT pageX, FX_FLOAT pageY);
   CPDFSDK_Annot* GetFocusAnnot();
   void SetFocusAnnot(CPDFSDK_Annot* pSDKAnnot, FX_UINT nFlag = 0) {
@@ -325,7 +325,7 @@ class CPDFSDK_PageView final {
                        double deltaY,
                        const CPDF_Point& point,
                        int nFlag);
-  FX_BOOL IsValidAnnot(CPDF_Annot* p) const;
+  bool IsValidAnnot(const CPDF_Annot* p) const;
   void GetCurrentMatrix(CPDF_Matrix& matrix) { matrix = m_curMatrix; }
   void UpdateRects(CFX_RectArray& rects);
   void UpdateView(CPDFSDK_Annot* pAnnot);