AU: Include the old/new kernel/rootfs size/hash in the update metadata.

omaha_hash_calculator.h

Index: omaha_hash_calculator.h
diff --git a/omaha_hash_calculator.h b/omaha_hash_calculator.h
index 7aa37e4338f71ba1eb1a4545d93a89c03761789a..5daba78b38f099e857a83a9771a05990d2fe1a1c 100644
--- a/omaha_hash_calculator.h
+++ b/omaha_hash_calculator.h
@@ -7,9 +7,10 @@
 
 #include <string>
 #include <vector>
+
 #include <openssl/sha.h>
-#include "base/basictypes.h"
-#include "base/logging.h"
+#include <base/basictypes.h>
+#include <base/logging.h>
 
 // Omaha uses base64 encoded SHA-256 as the hash. This class provides a simple
 // wrapper around OpenSSL providing such a formatted hash of data passed in.
@@ -28,6 +29,11 @@ class OmahaHashCalculator {
   // Returns true on success.
   bool Update(const char* data, size_t length);
 
+  // Updates the hash with up to |length| bytes of data from |file|. If |length|
+  // is negative, reads in and updates with the whole file. Returns the number
+  // of bytes that the hash was updated with, or -1 on error.
+  off_t UpdateFile(const std::string& name, off_t length);
+
   // Call Finalize() when all data has been passed in. This method tells
   // OpenSSl that no more data will come in and base64 encodes the resulting
   // hash.