update_engine: Rename "chromeos" -> "brillo" in include paths and namespaces

libchromeos is transitioning to libbrillo and chromeos namespaces
and include directory is changing to brillo.

Bug: 24872993
Change-Id: I770659a95be380a50fe3b2ba9f91d65818f40945
diff --git a/omaha_request_action.h b/omaha_request_action.h
index ec71238..f1b81ec 100644
--- a/omaha_request_action.h
+++ b/omaha_request_action.h
@@ -25,7 +25,7 @@
 #include <string>
 #include <vector>
 
-#include <chromeos/secure_blob.h>
+#include <brillo/secure_blob.h>
 #include <curl/curl.h>
 
 #include "update_engine/action.h"
@@ -311,7 +311,7 @@
   bool ping_only_;
 
   // Stores the response from the omaha server
-  chromeos::Blob response_buffer_;
+  brillo::Blob response_buffer_;
 
   // Initialized by InitPingDays to values that may be sent to Omaha
   // as part of a ping message. Note that only positive values and -1