AU: Try delta updates first, then full updates
Also, some bug fixes.
Review URL: http://codereview.chromium.org/492008
diff --git a/update_metadata.proto b/update_metadata.proto
index 61b4965..42880da 100644
--- a/update_metadata.proto
+++ b/update_metadata.proto
@@ -102,6 +102,8 @@
}
// If present, there is data associated with this File object and
// data_offset and data_size must be set.
+ // If a file object doesn't have this set, it means the data is
+ // unchanged from the old version of the file.
optional DataFormat data_format = 4;
// The offset into the delta file where the data (if any) is stored
optional uint32 data_offset = 5;