update_payload: Regenerate protobuf to include IMGDIFF.

Generated from update_metadata.proto using protoc 2.5.0

BUG=b:26456666
TEST=./checker_unittest.py

Change-Id: I9dc7db00be8afb2f78e80bec910f9ca83a55a9a1
Reviewed-on: https://chromium-review.googlesource.com/329237
Commit-Ready: Sen Jiang <senj@chromium.org>
Tested-by: Sen Jiang <senj@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
diff --git a/scripts/update_payload/common.py b/scripts/update_payload/common.py
index 80e2501..88cd6ed 100644
--- a/scripts/update_payload/common.py
+++ b/scripts/update_payload/common.py
@@ -44,8 +44,9 @@
   ZERO = _CLASS.ZERO
   DISCARD = _CLASS.DISCARD
   REPLACE_XZ = _CLASS.REPLACE_XZ
+  IMGDIFF = _CLASS.IMGDIFF
   ALL = (REPLACE, REPLACE_BZ, MOVE, BSDIFF, SOURCE_COPY, SOURCE_BSDIFF, ZERO,
-         DISCARD, REPLACE_XZ)
+         DISCARD, REPLACE_XZ, IMGDIFF)
   NAMES = {
       REPLACE: 'REPLACE',
       REPLACE_BZ: 'REPLACE_BZ',
@@ -55,7 +56,8 @@
       SOURCE_BSDIFF: 'SOURCE_BSDIFF',
       ZERO: 'ZERO',
       DISCARD: 'DISCARD',
-      REPLACE_XZ: 'REPLACE_XZ'
+      REPLACE_XZ: 'REPLACE_XZ',
+      IMGDIFF: 'IMGDIFF',
   }
 
   def __init__(self):