DevTools: [timeline] regression: do not collect trace events by default.

Tracing infrastructure enables by default all standard events if no not disabled categories were specified.
So we need to explicitly exclude enabled by default categories.

BUG=361045

Review URL: https://codereview.chromium.org/370793004

git-svn-id: svn://svn.chromium.org/blink/trunk@177556 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: NetworkPanel: do not track list of requests.

BUG=

Review URL: https://codereview.chromium.org/368003003

git-svn-id: svn://svn.chromium.org/blink/trunk@177557 bbb929c8-8fbe-4397-9dbb-9b2b20218538