add error code for screen drawing failure

This patch adds error code for screen drawing failure.

BUG=none
BRANCH=tot
TEST=Tested on Glados

Change-Id: I04b349fd2c0bc539338b7ee27b8fa9544c85c873
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/315257
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/firmware/include/vboot_api.h b/firmware/include/vboot_api.h
index ff858ac..95ef21d 100644
--- a/firmware/include/vboot_api.h
+++ b/firmware/include/vboot_api.h
@@ -121,6 +121,8 @@
 	/* No image present (returned from VbGbbReadImage() for missing image) */
 	VBERROR_NO_IMAGE_PRESENT              = 0x10026,
 
+	/* failed to draw screen */
+	VBERROR_SCREEN_DRAW                   = 0x10027,
 	/* VbExEcGetExpectedRWHash() may return the following codes */
 	/* Compute expected RW hash from the EC image; BIOS doesn't have it */
 	VBERROR_EC_GET_EXPECTED_HASH_FROM_IMAGE = 0x20000,