refactor: Event and EventTarget implementations (#4707)

Refactors Event and EventTarget so that they better encapsulate their
non-public data as well as are more forward compatible with things like
DOM Nodes.

Moves `dom_types.ts` -> `dom_types.d.ts` which was always the intention,
it was a legacy of when we used to build the types from the code and the
limitations of the compiler.  There was a lot of cruft in `dom_types`
which shouldn't have been there, and mis-alignment to the DOM standards.
This generally has been eliminated, though we still have some minor
differences from the DOM (like the removal of some deprecated
methods/properties).

Adds `DOMException`.  Strictly it shouldn't inherit from `Error`, but
most browsers provide a stack trace when one is thrown, so the behaviour
in Deno actually better matches the browser.

`Event` still doesn't log to console like it does in the browser.  I
 wanted to get this raised and that could be an enhancement later on (it
 currently doesn't either).

1 files changed, 1 insertions, 1 deletions

diff --git a/cli/js/web/request.ts b/cli/js/web/request.ts
index 96edaf59e..6a5d92a2b 100644
--- a/cli/js/web/request.ts
+++ b/cli/js/web/request.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import * as headers from "./headers.ts";
 import * as body from "./body.ts";
-import * as domTypes from "./dom_types.ts";
+import * as domTypes from "./dom_types.d.ts";
 import * as streams from "./streams/mod.ts";
 
 const { Headers } = headers;