WK2: Programatic scroll requests during scroll or zoom animation to reveal focused element are ignored.

[Enrica Casucci]

Given the asynchronous scrolling model of WK2 on iOS, we can receive a request to scroll from JavaScript while the UI process is still animating to reveal the focused input element.
This breaks the behavior of pages like www.amazon.co.jp on iOS.

<rdar://problem/16468462>

[Enrica Casucci]

Created attachment 231018 [details]
Patch

[Benjamin Poulain]

Comment on attachment 231018 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=231018&action=review

> Source/WebCore/dom/Element.cpp:1983
> -    if (document().page())
> -        document().page()->chrome().client().elementDidFocus(this);
> -
>      RefPtr<FocusEvent> event = FocusEvent::create(eventNames().focusEvent, false, false, document().defaultView(), 0, oldFocusedElement);
>      EventDispatcher::dispatchEvent(this, event.release());
> +    if (document().page())
> +        document().page()->chrome().client().elementDidFocus(this);
>  }

As discussed: let's move this on a separate patch, and handle the programmatic scroll.

> Source/WebCore/platform/ScrollableArea.h:72
> +    virtual bool inProgrammaticScroll() const { return false; }

Please move this to ScrollView.

You should also add override on FrameView's implementation.

> Source/WebKit2/UIProcess/API/Cocoa/WKWebView.mm:118
> +    BOOL _isAnimatingScrollOrZoom;

Let's try to remove this and stop the animations systematically.

We will need a more generic heuristic to solve conflicts between user gesture and animation origination from WebProcess's requests.

[Enrica Casucci]

Committed revision 168447.