It's important in multi-session case, each agent should cleanup own breakpoints on disabled. R=dgozman@chromium.org Bug: none Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel Change-Id: I1b2182aa01e74c7e9f36addf998c779d1d32feef Reviewed-on: https://chromium-review.googlesource.com/594272 Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org> Reviewed-by: Dmitry Gozman <dgozman@chromium.org> Cr-Commit-Position: refs/heads/master@{#47103}