When I update suuuuuper old Chromium repositories, I occasionally get that stupid Checksum mismatch from svn. It happens often enough that it's a thing, but uncommonly enough that I forget how to fix it each time. So, FOR PROSPERITY:
Checksum mismatch: trunk/src/chrome/test/functional/search_engines.py 5d1082dfc3e6363ece792d7cd49fde0a7ce9c6df
Then proooobably what happens was search_engines.py downloaded wonky or something such that the hash no longer came to be the correct thing. So solution:
See what was the revision number of the last change on the file:
git svn log chrome/test/functional/search_engines.py
Reset svn to be closest parent before that revision:
git svn reset -r62248 -p
git svn fetch!
Dance at your success.