Fix build of pdf_hint_table_fuzzer.

core/fpdfapi/fpdf_parser/cpdf_dictionary.h

Index: core/fpdfapi/fpdf_parser/cpdf_dictionary.h
diff --git a/core/fpdfapi/fpdf_parser/cpdf_dictionary.h b/core/fpdfapi/fpdf_parser/cpdf_dictionary.h
index 07903f5bd79bac2bef446692f38495309debdbef..e3fd59457552d51962de73cc5288ac18fe3b2842 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_dictionary.h
+++ b/core/fpdfapi/fpdf_parser/cpdf_dictionary.h
@@ -23,6 +23,7 @@ class CPDF_Dictionary : public CPDF_Object {
   using iterator = std::map<CFX_ByteString, CPDF_Object*>::iterator;
   using const_iterator = std::map<CFX_ByteString, CPDF_Object*>::const_iterator;
 
+  CPDF_Dictionary();
   explicit CPDF_Dictionary(const CFX_WeakPtr<CFX_ByteStringPool>& pPool);
 
   // CPDF_Object.