Revert "Split implementation of EventListener and EventHandler"

This reverts commit da27378f03ea3dc4bdba82e3cb1d13ad2fef7a7c.

Reason for revert: This CL caused many crashes in the wild. (crbug.com/881348)

Original change's description:
> Split implementation of EventListener and EventHandler
>
> This CL add new class blink::V8EventListenerImpl which implements
> ONLY EventListener (not EventHandler). It has a blink::V8EventListener
> which inherits blink::CallbackInterfaceBase. As a result, EventListener
> will start to handle incumbent realm. EventHandler will still be
> offered by blink::V8AbstractEventListener (this class is renamed to
> blink::V8AbstractEventHandler in this CL) after this CL submitted.
> Also, entry realm was set to wrong one (event target's one) with
> blink::V8AbstractEventLisntener so this CL set it to listener's one as
> defined in standard.
>
> Regarding crbug.com/872138 :
> Current blink::V8AbstractEventListener implements both of EventListener
> and EventHandler, so I am trying to implement new class for
> EventListener first to separate these. EventHandler will be modified in following CLs.
>
> Regarding crbug.com/878658 :
> This CL modifies expectation file for layout test:
> fast/events/touch/gesture/gesture-tap-frame-removed.html
> This is because event listener starts to remember incumbent realm after
> this CL and it results in incorrect behavior as explained in the BUG.
> This is not a regression, but have to be resolved in following CLs.
>
> Bug: 872138, 878658, 606900, 849236
> Change-Id: I4bf7fe2f4fd51287f873c2377edfd57e4bb2a54a
> Reviewed-on: https://chromium-review.googlesource.com/1172234
> Commit-Queue: Yuki Yamada <yukiy@google.com>
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
> Reviewed-by: Hayato Ito <hayato@chromium.org>
> Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#588748}

TBR=peria@chromium.org,yukishiino@chromium.org,hayato@chromium.org,haraken@chromium.org,yukiy@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 872138, 878658, 606900, 849236, 881348
Change-Id: Ie981df66657c8868c769cb8d18bf799605cfd004
Reviewed-on: https://chromium-review.googlesource.com/1212202
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589421}
34 files changed