DevTools: Make frameworks work with "custom" breakpoints (DOM, XHR, Events).

BUG=267592
R=pfeldman, yurys

Review URL: https://codereview.chromium.org/304563002

git-svn-id: svn://svn.chromium.org/blink/trunk@175136 bbb929c8-8fbe-4397-9dbb-9b2b20218538