Fix typo in cpdf_occontext.cpp

Use loop index `i` as intended instead of literal `1`.

The change is detected by one file in the corpus which is updated
along with the code.

Bug: pdfium:1624
Change-Id: Id6b5bcf713e6844776585a5d1eabe49e4e174c26
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/77290
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Hui Yingst <nigi@chromium.org>
diff --git a/DEPS b/DEPS
index f8dfb1a..b9ef6e4 100644
--- a/DEPS
+++ b/DEPS
@@ -89,7 +89,7 @@
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling pdfium_tests
   # and whatever else without interference from each other.
-  'pdfium_tests_revision': '79c60bac7af87b386fd3df557eb782383e612a3a',
+  'pdfium_tests_revision': 'db1faf0ee5ab4e8be140dc1c0fc0031ab70a817c',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling skia
   # and whatever else without interference from each other.
diff --git a/core/fpdfapi/page/cpdf_occontext.cpp b/core/fpdfapi/page/cpdf_occontext.cpp
index a5751b0..aa84b97 100644
--- a/core/fpdfapi/page/cpdf_occontext.cpp
+++ b/core/fpdfapi/page/cpdf_occontext.cpp
@@ -214,7 +214,7 @@
 
   bool bValue = false;
   for (size_t i = 1; i < pExpression->size(); i++) {
-    const CPDF_Object* pOCGObj = pExpression->GetDirectObjectAt(1);
+    const CPDF_Object* pOCGObj = pExpression->GetDirectObjectAt(i);
     if (!pOCGObj)
       continue;