AU: Verify that the applied delta update matches the server-sent hashes.

Also, don't try to resume any delta update that fails for any reason
other than download transfer errors.

BUG=7348
TEST=unit tests, gmerged on device

Change-Id: Ice464b8d421256717d7909fd5fa46d762bd48952

Review URL: http://codereview.chromium.org/3599025
diff --git a/action_processor.h b/action_processor.h
index b2c1392..fc42a24 100644
--- a/action_processor.h
+++ b/action_processor.h
@@ -36,6 +36,7 @@
   kActionCodeDownloadHashMismatchError = 10,
   kActionCodeDownloadSizeMismatchError = 11,
   kActionCodeDownloadPayloadVerificationError = 12,
+  kActionCodeDownloadAppliedUpdateVerificationError = 13,
 };
 
 class AbstractAction;