Remove old EventListener and EventHandler

This is a clean-up for previous CL:
https://chromium-review.googlesource.com/c/chromium/src/+/1215512

After submitted the previous CL, these old classes are not used from
anywhere:
    blink::V8AbstractEventHandler
    blink::V8EventListenerOrEventHandler
    blink::V8ErrorHandler
    blink::V8LazyEventListener
Therefore, this CL removes them.

Bug: 872138
Change-Id: I44e9026148e6db24f44b52c138523cce55eacd7d
Reviewed-on: https://chromium-review.googlesource.com/c/1273355
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Hayato Ito <hayato@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Yamada <yukiy@google.com>
Cr-Commit-Position: refs/heads/master@{#598707}
11 files changed