Rialto: disable injection of decryptor element

Change-Id: I5ce9f9d9027bbedb359e99c251d3f520b683b1cd
diff --git a/src/third_party/starboard/rdk/shared/drm/gst_decryptor_ocdm.cc b/src/third_party/starboard/rdk/shared/drm/gst_decryptor_ocdm.cc
index 2d51658..85d8f20 100644
--- a/src/third_party/starboard/rdk/shared/drm/gst_decryptor_ocdm.cc
+++ b/src/third_party/starboard/rdk/shared/drm/gst_decryptor_ocdm.cc
@@ -556,6 +556,12 @@
 }  // namespace
 
 GstElement *CreateDecryptorElement(const gchar* name) {
+  static bool isRialtoOCDM = ([](){
+    const char* ocdmLibName = getenv("OCDM_LIBRARY");
+    return ocdmLibName && strstr(ocdmLibName, "libocdmRialto.so");
+  })();
+  if (isRialtoOCDM)
+    return nullptr;
   return GST_ELEMENT ( g_object_new (COBALT_OCDM_DECRYPTOR_TYPE, name) );
 }