Fix an infinite loop parsing in CPDF_SyntaxParser::GetObject()

fpdfsdk/src/fpdfview_embeddertest.cpp

 // Copyright 2015 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 #include <string>
 
 #include "fpdfsdk/src/fpdfview_c_api_test.h"
 #include "public/fpdfview.h"
 #include "testing/embedder_test.h"
@@ skipping 203 matching lines @@
 // the fix, LoadAllCrossRefV4 will return false after detecting a cross
 // reference loop. Cross references will be rebuilt successfully.
 TEST_F(FPDFViewEmbeddertest, CrossRefV4Loop) {
   EXPECT_TRUE(OpenDocument("bug_xrefv4_loop.pdf"));
 }
 
 // The test should pass when circular references to ParseIndirectObject will not
 // cause infinite loop.
 TEST_F(FPDFViewEmbeddertest, Hang_343) {
   EXPECT_FALSE(OpenDocument("bug_343.pdf"));
+}
+
+// The test should pass when the absence of 'Contents' field in a signature
+// dictionary will not cause an infinite loop in CPDF_SyntaxParser::GetObject().
+TEST_F(FPDFViewEmbeddertest, Hang_344) {
+  EXPECT_FALSE(OpenDocument("bug_344.pdf"));
 }