Add test to ensure that URLs that redirect inside the PDF plugin fail to load

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index a05a82eff108f905d87aa0606122e2dcc7dba32a..1eb1694cffd936d6b52f22aa72786703836ffb40 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -1094,6 +1094,10 @@ void PDFiumEngine::OnDocumentComplete() {
   FinishLoadingDocument();
 }
 
+void PDFiumEngine::DocumentLoadFailed() {
+  client_->DocumentLoadFailed();
+}
+
 void PDFiumEngine::FinishLoadingDocument() {
   DCHECK(doc_loader_.IsDocumentComplete() && doc_);