GitLab

- Decode the result of subprocess.Popen() so that the stdout/stderr
  result is str, not bytes.
- Use dict.items() instead of dict.iteritems().
- If the return of map() needs to be a list, use list comprehension.
- Use range() instead of xrange().
- Tuple parameter unpacking is removed on Python3, refactor its usage.
- struct.pack() doesn't accept str, convert arguments as bytes.
- plistlib has several API changes. Replace removed.
  functions (readPlistFromString). Still have some warnings like this:
  "The readPlist function is deprecated, use load() instead"
- _GetOutputNoError() in tweak_info_plist.py has no usage. Removed.

No intended behavior change.

Bug: 941669
Change-Id: Ibc204fad8b56e864a083046559133403dcf99fe3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2392289Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805790}