changing-files: drop the now useless changelogrevision argument

Since all filename are now included in the sidedata block, we no longer need to decode the `files` from the revision.

Differential Revision: https://phab.mercurial-scm.org/D9091

mercurial/changelog.py

@@ -305,7 +305,7 b' class changelogrevision(object):'
         if self._changes is not None:
             return self._changes
         if self._cpsd:
-            changes = metadata.decode_files_sidedata(self, self._sidedata)
+            changes = metadata.decode_files_sidedata(self._sidedata)
         else:
             changes = metadata.ChangingFiles(
                 touched=self.files or (),

mercurial/metadata.py

@@ -430,7 +430,7 b' def encode_files_sidedata(files):'
     return {sidedatamod.SD_FILES: b''.join(chunks)}
 
 
-def decode_files_sidedata(changelogrevision, sidedata):
+def decode_files_sidedata(sidedata):
     md = ChangingFiles()
     raw = sidedata.get(sidedatamod.SD_FILES)