Add CPDF_{Array,Dictionary}Locker to catch illegal iteration patterns.

Move begin/end methods onto locker object which tracks whether
iterators are in existence.

Change-Id: Ia869f313fce48d10a0d0180d0cc083eed6ea1584
Reviewed-on: https://pdfium-review.googlesource.com/c/44070
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/core/fpdfapi/parser/cpdf_object_unittest.cpp b/core/fpdfapi/parser/cpdf_object_unittest.cpp
index e5b322ff42..c3ec3aeddb 100644
--- a/core/fpdfapi/parser/cpdf_object_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_object_unittest.cpp
@@ -138,9 +138,9 @@ class PDFObjectsTest : public testing::Test {
         const CPDF_Dictionary* dict2 = obj2->AsDictionary();
         if (dict1->size() != dict2->size())
           return false;
-        for (CPDF_Dictionary::const_iterator it = dict1->begin();
-             it != dict1->end(); ++it) {
-          if (!Equal(it->second.get(), dict2->GetObjectFor(it->first)))
+        CPDF_DictionaryLocker locker1(dict1);
+        for (const auto& item : locker1) {
+          if (!Equal(item.second.get(), dict2->GetObjectFor(item.first)))
             return false;
         }
         return true;