Avoid an undefined shift in ReadPageHintTable().

core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp

Index: core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
diff --git a/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp b/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
index 63a64a302691f5b8ca63cdf1b1f674cd437d8c4a..245862d90ba1bcb9b6613b507278447836b6bb44 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
@@ -109,6 +109,9 @@ FX_BOOL CPDF_HintTables::ReadPageHintTable(CFX_BitStream* hStream) {
   // Item 13: Skip Item 13 which has 16 bits.
   hStream->SkipBits(16);
 
+  if (dwSharedObjBits >= 40)

[Tom Sepez, 2016/08/12 15:29:12]

nit: can we make this kMumbleSomethingBits add add the comment about generosity
when we declare it?

[Lei Zhang, 2016/08/13 02:47:14]

Done.

+    return FALSE;
+
   CPDF_Object* pPageNum = m_pLinearizedDict->GetDirectObjectBy("N");
   int nPages = pPageNum ? pPageNum->GetInteger() : 0;
   if (nPages < 1)