Prevent cloned arrays/dictionaries from having nullptrs.

core/fpdfapi/fpdf_parser/cpdf_array.cpp

Index: core/fpdfapi/fpdf_parser/cpdf_array.cpp
diff --git a/core/fpdfapi/fpdf_parser/cpdf_array.cpp b/core/fpdfapi/fpdf_parser/cpdf_array.cpp
index d588f339a7b45c09347e504b355dc8326025cb4a..efe0518d86d40166ae32927e31e02312ba7e1d4a 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_array.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_array.cpp
@@ -46,8 +46,10 @@ const CPDF_Array* CPDF_Array::AsArray() const {
 CPDF_Object* CPDF_Array::Clone(FX_BOOL bDirect) const {
   CPDF_Array* pCopy = new CPDF_Array();
   for (size_t i = 0; i < GetCount(); i++) {
-    CPDF_Object* value = m_Objects.at(i);
-    pCopy->m_Objects.push_back(value->Clone(bDirect));
+    CPDF_Object* pObj = m_Objects.at(i);
+    CPDF_Object* pCloneObj = pObj->Clone(bDirect);
+    if (pCloneObj)
+      pCopy->m_Objects.push_back(pCloneObj);
   }
   return pCopy;
 }