Rename ActionExitCode to ErrorCode

Nowadays ActionExitCode is used throughout the codebase so use a more
generic name to reflect this.

BUG=chromium:216507
TEST=unit tests pass

Change-Id: I23d1d7e2676443251dbc42ed137fd018aadfa8a3
Reviewed-on: https://gerrit.chromium.org/gerrit/49512
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: David Zeuthen <zeuthen@chromium.org>
Tested-by: David Zeuthen <zeuthen@chromium.org>
diff --git a/payload_state_interface.h b/payload_state_interface.h
index e092290..205cb91 100644
--- a/payload_state_interface.h
+++ b/payload_state_interface.h
@@ -56,7 +56,7 @@
   // This method should be called whenever an update attempt fails with the
   // given error code. We use this notification to update the payload state
   // depending on the type of the error that happened.
-  virtual void UpdateFailed(ActionExitCode error) = 0;
+  virtual void UpdateFailed(ErrorCode error) = 0;
 
   // Returns true if we should backoff the current download attempt.
   // False otherwise.