[poppler] Making OCG suppression be recursive

[Albert Astals Cid]

Hi the attached patch adds that if we do a Begin Marked Content that is 
suppressed and then we do a Begin Marked Content that is not suppressed 
without closing the first one, the operations are still not drawn.

This fixes bug 16093, i think it's the correct way but as Carlos and Brad have 
worked more on Optional Content i'd like some more input if possible (i know 
i'm asking for much :-))

Albert


diff --git a/poppler/Gfx.cc b/poppler/Gfx.cc
index 0eef5d3..b63d424 100644
--- a/poppler/Gfx.cc
+++ b/poppler/Gfx.cc
@@ -4216,7 +4216,13 @@ void Gfx::pushMarkedContent() {
 }

 GBool Gfx::contentIsHidden() {
-  return mcStack && mcStack->ocSuppressed;
+  MarkedContentStack *mc = mcStack;
+  bool hidden = mc && mc->ocSuppressed;
+  while (!hidden && mc && mc->next) {
+    mc = mc->next;
+    hidden = mc->ocSuppressed;
+  }
+  return hidden;
 }

 void Gfx::opBeginMarkedContent(Object args[], int numArgs) {