diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 508ff63..318a822 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -700,6 +700,7 @@
 DEFINE_string(picture, "", "Path to single picture.");
 DEFINE_bool(sort, false, "Sort samples by title.");
 DEFINE_bool(list, false, "List samples?");
+DEFINE_string(key, "", "");  // dummy to enable gm tests that have platform-specific names
 #ifdef SAMPLE_PDF_FILE_VIEWER
 DEFINE_string(pdfPath, "", "Path to direcotry of pdf files.");
 #endif