Executing custom element lifecycle callbacks while paused in debugger.

It was not invoking the callbacks if canInvokeCallback was false, but this is primarily for blocking async background callbacks from occurring while paused. Since custom element callbacks should only be caused by code running while paused (via the console), then these should be OK.

BUG=282476

Review URL: https://codereview.chromium.org/101003004

git-svn-id: svn://svn.chromium.org/blink/trunk@164160 bbb929c8-8fbe-4397-9dbb-9b2b20218538