Fix a crasher caused by an invalid index in CXFA_LayoutPageMgr::GetPage()

BUG=pdfium:289
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1472383003 .

1 files changed, 3 insertions, 4 deletions

diff --git a/xfa/src/fxfa/src/parser/xfa_layout_pagemgr_new.cpp b/xfa/src/fxfa/src/parser/xfa_layout_pagemgr_new.cpp
index 262a0be717..f83b772003 100644
--- a/xfa/src/fxfa/src/parser/xfa_layout_pagemgr_new.cpp
+++ b/xfa/src/fxfa/src/parser/xfa_layout_pagemgr_new.cpp
@@ -603,10 +603,9 @@ int32_t CXFA_LayoutPageMgr::GetPageCount() const {
   return m_PageArray.GetSize();

 }

 IXFA_LayoutPage* CXFA_LayoutPageMgr::GetPage(int32_t index) const {

-  if (m_PageArray.GetSize() > index) {

-    return m_PageArray[index];

-  }

-  return NULL;

+  if (index < 0 || index >= m_PageArray.GetSize())

+    return nullptr;

+  return m_PageArray[index];

 }

 int32_t CXFA_LayoutPageMgr::GetPageIndex(const IXFA_LayoutPage* pPage) const {

   // FIXME: Find() method should take const.