Traverse PDF page tree only once in CPDF_Document Try 3

core/fpdfapi/parser/cpdf_document_unittest.cpp

Index: core/fpdfapi/parser/cpdf_document_unittest.cpp
diff --git a/core/fpdfapi/parser/cpdf_document_unittest.cpp b/core/fpdfapi/parser/cpdf_document_unittest.cpp
index 9336626f45989be83afd6f10b4dfd305df8f35f4..3fa5f3f7f995649164473b9c01083c833693e346 100644
--- a/core/fpdfapi/parser/cpdf_document_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_document_unittest.cpp
@@ -116,6 +116,29 @@ TEST_F(cpdf_document_test, GetPagesReverseOrder) {
   EXPECT_FALSE(page);
 }
 
+TEST(cpdf_document, GetPagesInDisorder) {
+  std::unique_ptr<CPDF_TestDocumentForPages> document =
+      pdfium::MakeUnique<CPDF_TestDocumentForPages>();
+
+  CPDF_Dictionary* page = document->GetPage(1);
+  ASSERT_TRUE(page);
+  ASSERT_TRUE(page->GetObjectFor("PageNumbering"));
+  EXPECT_EQ(1, page->GetIntegerFor("PageNumbering"));
+
+  page = document->GetPage(3);
+  ASSERT_TRUE(page);
+  ASSERT_TRUE(page->GetObjectFor("PageNumbering"));
+  EXPECT_EQ(3, page->GetIntegerFor("PageNumbering"));
+
+  page = document->GetPage(7);
+  EXPECT_FALSE(page);
+
+  page = document->GetPage(6);
+  ASSERT_TRUE(page);
+  ASSERT_TRUE(page->GetObjectFor("PageNumbering"));
+  EXPECT_EQ(6, page->GetIntegerFor("PageNumbering"));
+}
+
 TEST_F(cpdf_document_test, UseCachedPageObjNumIfHaveNotPagesDict) {
   // ObjNum can be added in CPDF_DataAvail::IsPageAvail, and PagesDict
   // can be not exists in this case.