Remove unused include.

R=dcarney@chromium.org
BUG=276323

Review URL: https://codereview.chromium.org/230613006

git-svn-id: svn://svn.chromium.org/blink/trunk@171145 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: merge tracing agent into tracing model

BUG=

Review URL: https://codereview.chromium.org/230303003

git-svn-id: svn://svn.chromium.org/blink/trunk@171146 bbb929c8-8fbe-4397-9dbb-9b2b20218538