Fix O(n^2) behaviour in parser.

Despite what the c++11 spec says, std::list::size() is
still O(n), not O(1).

R=dsinclair@chromium.org, ochang@chromium.org

Review URL: https://codereview.chromium.org/1763443003 .

1 files changed, 1 insertions, 7 deletions

diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
index 301fca8969..77707624d2 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
@@ -462,13 +462,7 @@ void CPDF_FormObject::CalcBoundingBox() {
 CPDF_PageObject* CPDF_PageObjectList::GetPageObjectByIndex(int index) {
   if (index < 0 || index >= pdfium::CollectionSize<int>(*this))
     return nullptr;
-  int current = 0;
-  for (const auto& pObj : *this) {
-    if (index == current)
-      return pObj.get();
-    ++current;
-  }
-  return nullptr;
+  return (*this)[index].get();
 }
 
 CPDF_PageObjectHolder::CPDF_PageObjectHolder()