AU: pass whether or not we can tolerate a delta to the server

omaha_request_params.cc

Index: omaha_request_params.cc
diff --git a/omaha_request_params.cc b/omaha_request_params.cc
index 502f7b0602e50c64a7e1ef2667295950c029185d..1ab6f2cb5e2a6d12466fe3c6a86fee5f5e65e0de 100644
--- a/omaha_request_params.cc
+++ b/omaha_request_params.cc
@@ -38,6 +38,14 @@ bool OmahaRequestDeviceParams::Init() {
   app_id = OmahaRequestParams::kAppId;
   app_lang = "en-US";
   app_track = GetLsbValue("CHROMEOS_RELEASE_TRACK", "");
+  struct stat stbuf;
+  
+  // Deltas are only okay if the /.nodelta file does not exist.
+  // If we don't know (i.e. stat() returns some unexpected error),
+  // then err on the side of caution and say deltas are not okay
+  delta_okay = (stat((root_ + "/.nodelta").c_str(), &stbuf) < 0) &&
+               (errno == ENOENT);
+
   update_url = GetLsbValue("CHROMEOS_AUSERVER",
                            OmahaRequestParams::kUpdateUrl);
   return true;