Add a feature flag to allow or disallow writing RTF to the pasteboard when copying/dragging

[whsieh]

ccdf275

Add a feature flag to allow or disallow writing RTF to the pasteboard when copying/dragging
https://bugs.webkit.org/show_bug.cgi?id=265323
rdar://118419812

Reviewed by Richard Robinson.

On some Cocoa OS versions, the pasteboard will (if necessary) automatically convert HTML and web
archive data written to the pasteboard to RTF, RTFD, or archived `NSAttributedString` data when
pasting in an app that only consumes these native rich text formats.

When this behavior is available (guarded by `HAVE(PASTEBOARD_CONVERSION_FROM_HTML_TO_RTF)`), WebKit
no longer needs to eagerly write RTF, RTFD or attributed string representations of the selected text
to the pasteboard when copying or dragging text, since we can defer to system support for performing
this conversion on paste/drop.

Make some minor adjustments to pasteboard writing logic, to make the attributed string writing part
conditional on this new setting.

* Source/WTF/Scripts/Preferences/UnifiedWebPreferences.yaml:
* Source/WebCore/editing/Editor.h:
* Source/WebCore/editing/cocoa/EditorCocoa.mm:
(WebCore::populateRichTextDataIfNeeded):
(WebCore::Editor::writeSelectionToPasteboard):
(WebCore::Editor::writeSelection):

Canonical link: https://commits.webkit.org/271106@main

984fef7

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	❌ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	❌ 🧪 api-gtk
	✅ 🛠 tv-sim		✅ 🛠 jsc-armv7
✅ 🛠 🧪 merge	✅ 🛠 watch		✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 062a4da)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	❌ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim		✅ 🛠 jsc-armv7
	✅ 🛠 watch		✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch-sim

[rr-codes]

this could probably be refactored into a generic function since it’s the same few lines as above, but that’s probably overkill.

[whsieh]

It's not too unwieldy, though I'd need to pull the static dataInRTFDFormat / dataInRTFFormat helpers out into the public section so that I can use them here:

template<typename PasteboardContent>
void populateRichTextDataIfNeeded(PasteboardContent& content, const Document& document)
{
    if (!document.settings().writeRichTextDataWhenCopyingOrDragging())
        return;

    auto string = selectionAsAttributedString(document);
    content.dataInRTFDFormat = [string containsAttachments] ? Editor::dataInRTFDFormat(string.get()) : nullptr;
    content.dataInRTFFormat = Editor::dataInRTFFormat(string.get());
    content.dataInAttributedStringFormat = archivedDataForAttributedString(string.get());
}

Thanks for the review!

[webkit-early-warning-system]

EWS run on current version of this PR (hash 984fef7)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	❌ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	❌ 🧪 api-gtk
	✅ 🛠 tv-sim		✅ 🛠 jsc-armv7
✅ 🛠 🧪 merge	✅ 🛠 watch		✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 271106@main (ccdf275): https://commits.webkit.org/271106@main

Reviewed commits have been landed. Closing PR #20880 and removing active labels.