delta_generator: Include per-operation source hash.
This adds a src_sha256_hash field in the operation if minor version is 3.
Bug: 23182225
TEST=cros_workon_make update_engine --test
TEST=Generated a minor version 3 payload, the manifest is about 50% larger.
Change-Id: I0e363fca4de24bae64ac83930afdd42a6ddc21c9
diff --git a/payload_constants.h b/payload_constants.h
index 38cc075..d423eeb 100644
--- a/payload_constants.h
+++ b/payload_constants.h
@@ -40,6 +40,9 @@
// The minor version used by the A to B delta generator algorithm.
extern const uint32_t kSourceMinorPayloadVersion;
+// The minor version that allows per-operation source hash.
+extern const uint32_t kOpSrcHashMinorPayloadVersion;
+
// The kernel and rootfs partition names used by the BootControlInterface when
// handling update payloads with a major version 1. The names of the updated