[Cocoa] Accelerated filters are enabled by the wrong setting

[Said Abou-Hallawa]

There has been a confusion about how CoreImage filters can be enabled. There are two settings/feature controls which have been used:

1. CoreImageAcceleratedFilterRenderEnabled
2. AcceleratedFiltersEnabled

The first was used to enable CoreImage filters which also requires to have accelerated filters. It is also linked with the mini-browser experimental feature "CoreImage-Accelerated Filter Rendering". The use of it was mistakenly dropped in r286193 and AcceleratedFiltersEnabled has been used since then.

The second one was introduced by r102088 for the Chromium port back in 2011. There is nothing in WebKit enables this setting right now. And for Apple ports, I do not think there is any current plans for using IOSurfaces for software filters.

So I think to use the correct setting for enabling the CoreImage filters and to clean this area we need to do the following:

1. Delete the setting AcceleratedFiltersEnabled
2. Use CoreImageAcceleratedFilterRenderEnabled to enable CoreImage filters and to force using IOSurfaces for the intermediate filter images. This setting will be respected only if the filter chain can be rendered via CoreImage.
3. Fix the GTK unused parameter warning from FEColorMatrix::createApplier(), FEComponentTransfer::createApplier() and SourceGraphic::createApplier().

[Said Abou-Hallawa]

Created attachment 449508 [details]
Patch

[Said Abou-Hallawa]

Created attachment 449539 [details]
Patch

[Tim Horton]

Comment on attachment 449539 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=449539&action=review

> Source/WTF/Scripts/Preferences/WebPreferencesExperimental.yaml:414
>    webcoreOnChange: setNeedsRelayoutAllFrames

can we change the preference name to CoreImageAcceleratedFiltersEnabled or UseCoreImageForAcceleratedFilters? "filter render" is a weird term.

> Source/WebCore/css/CSSFilterImageValue.cpp:118
> +    auto renderingMode = renderer.page().acceleratedFilterRenderEnabled() ? RenderingMode::Accelerated : RenderingMode::Unaccelerated;

"acceleratedFilterRender*ing*Enabled" I think would read more correctly, but also it could be simplified as above.

[Said Abou-Hallawa]

Created attachment 449626 [details]
Patch

[Said Abou-Hallawa]

Created attachment 449627 [details]
Patch

[EWS]

Committed r288352 (246258@main): <https://commits.webkit.org/246258@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 449627 [details].

[Radar WebKit Bug Importer]

<rdar://problem/87868182>