fix: use OOPIF for webview tag (#13869)

* fix: use OOIF for webview tag

* fix: do not call GetNativeView for webview

* fix: OOIPF webview's WebContents is managed by embedder frame

* fix: guest view can not be focused

* fix: clear zoom controller when guest is destroyed

* fix: implement the webview resize event

The webview is no longer a browser plugin with the resize event, use
ResizeObserver instead.

* test: disable failed tests due to OOPIF webview

* fix: embedder can be destroyed earlier than guest

This happens when embedder is manually destroyed.

* fix: don't double attach

* fix: recreate iframe when webview is reattached

* fix: resize event may happen very early

* test: some tests are working after OOPIF webview

* chore: remove unused browser plugin webview code

* fix: get embedder via closure

When the "destroyed" event is emitted, the entry in guestInstances would be
cleared.

* chore: rename browserPluginNode to internalElement

* test: make the visibilityState test more robust

* chore: guestinstance can not work with OOPIF webview

* fix: element could be detached before got response from browser

atom/browser/web_contents_zoom_controller.h

@@ -24,6 +24,7 @@ class WebContentsZoomController
     virtual void OnZoomLevelChanged(content::WebContents* web_contents,
                                     double level,
                                     bool is_temporary) {}
+    virtual void OnZoomControllerWebContentsDestroyed() {}
 
    protected:
     virtual ~Observer() {}