Convert CPDF_StructElement::CountKids to size_t

This CL changes CountKids to not used CollectionSize and returns size_t
directly. Callers updated as needed.

Bug: pdfium:774
Change-Id: I8862218e62cd13be9473fa8116afd29cd3afde04
Reviewed-on: https://pdfium-review.googlesource.com/19510
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

1 files changed, 7 insertions, 3 deletions

diff --git a/fpdfsdk/fpdf_structtree.cpp b/fpdfsdk/fpdf_structtree.cpp
index b1fca65015..483d894f6e 100644
--- a/fpdfsdk/fpdf_structtree.cpp
+++ b/fpdfsdk/fpdf_structtree.cpp
@@ -99,15 +99,19 @@ FPDF_StructElement_GetTitle(FPDF_STRUCTELEMENT struct_element,
 FPDF_EXPORT int FPDF_CALLCONV
 FPDF_StructElement_CountChildren(FPDF_STRUCTELEMENT struct_element) {
   CPDF_StructElement* elem = ToStructTreeElement(struct_element);
-  return elem ? elem->CountKids() : -1;
+  if (!elem)
+    return -1;
+
+  pdfium::base::CheckedNumeric<int> tmp_size = elem->CountKids();
+  return tmp_size.ValueOrDefault(-1);
 }
 
 FPDF_EXPORT FPDF_STRUCTELEMENT FPDF_CALLCONV
 FPDF_StructElement_GetChildAtIndex(FPDF_STRUCTELEMENT struct_element,
                                    int index) {
   CPDF_StructElement* elem = ToStructTreeElement(struct_element);
-  if (!elem || index < 0 || index >= elem->CountKids())
+  if (!elem || index < 0 || static_cast<size_t>(index) >= elem->CountKids())
     return nullptr;
 
-  return elem->GetKidIfElement(index);
+  return elem->GetKidIfElement(static_cast<size_t>(index));
 }