Fix stack overflow in object Clone() functions

core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp

Index: core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp
diff --git a/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp b/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp
index 78b88a1b2f1a84027057b72047a41b871f4fd162..0613c0d7819327498a16ad3133e2f1a26339cfc5 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp
@@ -44,10 +44,21 @@ const CPDF_Dictionary* CPDF_Dictionary::AsDictionary() const {
   return this;
 }
 
-CPDF_Object* CPDF_Dictionary::Clone(FX_BOOL bDirect) const {
+CPDF_Object* CPDF_Dictionary::Clone() const {
+  return CloneDeRef(false);
+}
+
+CPDF_Object* CPDF_Dictionary::CloneWithCheck(
+    bool bDirect,
+    std::set<const CPDF_Object*>* pVisited) const {
+  pVisited->insert(this);
   CPDF_Dictionary* pCopy = new CPDF_Dictionary();
-  for (const auto& it : *this)
-    pCopy->m_Map.insert(std::make_pair(it.first, it.second->Clone(bDirect)));
+  for (const auto& it : *this) {
+    auto value = it.second;

[Lei Zhang, 2016/08/18 15:16:44]

auto* ?

[Wei Li, 2016/08/18 22:02:30]

Changed to actual type

+    if (!pdfium::ContainsKey(*pVisited, value))

[dsinclair, 2016/08/18 14:04:31]

nit: add {}'s

[Wei Li, 2016/08/18 22:02:30]

Done.

+      pCopy->m_Map.insert(
+          std::make_pair(it.first, value->CloneWithCheck(bDirect, pVisited)));
+  }
   return pCopy;
 }