CCA: Switch python style to PEP8

Chromium switched to PEP8 for new code. Reformatted with the new config,
and rename function from CamelCase to snake_case.
https://chromium.googlesource.com/chromium/src/+/master/styleguide/python/python.md

Bug: 1019581
Test: yapf utils/cca.py
Tricium: disable
Change-Id: I9607653182cd28c6df137bf9b4d2fc07b23aa438
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1994851Reviewed-by: Wei Lee <wtlee@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#730082}

chrome/browser/resources/chromeos/camera/.style.yapf

 [style]
-based_on_style = chromium
+based_on_style = pep8