Timeline: add disabled-by-default-devtools.timeline{,.frame} to category filter

This prepares inspector for switching chromium-side trace events used
for building timeline to the category names consistent with the rest of
timeline trace-based instrumentation in blink.

BUG=361045

Review URL: https://codereview.chromium.org/328723002

git-svn-id: svn://svn.chromium.org/blink/trunk@175891 bbb929c8-8fbe-4397-9dbb-9b2b20218538