test: video: Export the video-checking functions

We want to check the display contents in expo tests, so move the two
needed functions to a new header file.

Rename them to have a video_ prefix.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/test/video.h b/include/test/video.h
new file mode 100644
index 0000000..000fd70
--- /dev/null
+++ b/include/test/video.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2013 Google, Inc.
+ */
+
+#ifndef __TEST_VIDEO_H
+#define __TEST_VIDEO_H
+
+#include <stdbool.h>
+
+struct udevice;
+struct unit_test_state;
+
+/**
+ * video_compress_fb() - Compress the frame buffer and return its size
+ *
+ * We want to write tests which perform operations on the video console and
+ * check that the frame buffer ends up with the correct contents. But it is
+ * painful to store 'known good' images for comparison with the frame
+ * buffer. As an alternative, we can compress the frame buffer and check the
+ * size of the compressed data. This provides a pretty good level of
+ * certainty and the resulting tests need only check a single value.
+ *
+ * @uts:	Test state
+ * @dev:	Video device
+ * @use_copy:	Use copy frame buffer if available
+ * Return: compressed size of the frame buffer, or -ve on error
+ */
+int video_compress_fb(struct unit_test_state *uts, struct udevice *dev,
+		      bool use_copy);
+
+/**
+ * check_copy_frame_buffer() - Compare main frame buffer to copy
+ *
+ * If the copy frame buffer is enabled, this compares it to the main
+ * frame buffer. Normally they should have the same contents after a
+ * sync.
+ *
+ * @uts:	Test state
+ * @dev:	Video device
+ * Return: 0, or -ve on error
+ */
+int video_check_copy_fb(struct unit_test_state *uts, struct udevice *dev);
+
+#endif