[visionOS] Web process hangs under createDragImageFor{Link|Selection} when starting a drag for the first time

[whsieh]

75ce30b

[visionOS] Web process hangs under createDragImageFor{Link|Selection} when starting a drag for the first time
https://bugs.webkit.org/show_bug.cgi?id=286819
rdar://141448897

Reviewed by Abrar Rahman Protyasha.

On visionOS, when starting a drag for the first time on a webpage, we end up spending a large amount
of time underneath `+[UIScreen initialize]` within the web process, while trying to render the drag
image using the helpers in `DragImageIOS.mm` (which instantiate `UIGraphicsImageRenderer`). This
causes the web process to hang briefly, which in turn may cause the drag to fail entirely.

To mitigate this, we refactor these helpers such that they no longer rely (indirectly) on
instantiating `UIScreen` via `UIGraphicsImageRenderer`, and instead use `WebCore::ImageBuffer` and
`sinkIntoNativeImage`. See below for more details.

* Source/WebCore/dom/DataTransfer.cpp:
(WebCore::DataTransfer::setDragImage):
(WebCore::DataTransfer::updateDragImage):
(WebCore::DataTransfer::createDragImage const):
(WebCore::DragImageLoader::DragImageLoader):
(WebCore::DragImageLoader::imageChanged):
* Source/WebCore/dom/DataTransfer.h:
* Source/WebCore/dom/DataTransferMac.mm:
(WebCore::DataTransfer::createDragImage const):

Plumb the `Document` through here, so that we can get the `deviceScaleFactor` / `HostWindow` and
pass them through to `createDragImageFromImage`.

* Source/WebCore/page/DragController.cpp:
(WebCore::DragController::startDrag):
(WebCore::DragController::doImageDrag):

Pass the device scale factor and host window into `createDragImageFromImage`.

* Source/WebCore/platform/DragImage.cpp:
(WebCore::createDragImageFromImage):
* Source/WebCore/platform/DragImage.h:
* Source/WebCore/platform/cocoa/DragImageCocoa.mm:
(WebCore::createDragImageFromImage):
* Source/WebCore/platform/gtk/DragImageGtk.cpp:
(WebCore::createDragImageFromImage):
* Source/WebCore/platform/ios/DragImageIOS.mm:
(WebCore::scaleDragImage):

Make this helper function a no-op. This logic was actually unnecessary from the start, since the
drag image will always perform lift and cancel animations using targeted previews which scale to fit
the bounds of the dragged element. As such, there's no need to artificially clamp the drag image to
an arbitrary maximum size of 400x400.

(WebCore::createDragImageFromImage):

Make this take both a device scale factor and `HostWindow`, which allows us to create a new
`ImageBuffer`, paint the given image into the buffer (scaling down if needed), and finally extract
a native image from the image buffer. This avoids the need for `UIGraphicsImageRenderer` entirely.

(WebCore::deleteDragImage):
(WebCore::cgImageFromTextIndicator):
(WebCore::createDragImageForLink):

Remove logic for creating a drag image representing a link (URL) platter. This has been unnecessary
ever since we (1) adopted `+[UIDragPreview previewForURL:title:]`, and (2) use text indicator for
the lift preview. Instead, just return the content image of the text indicator here.

(WebCore::createDragImageForSelection):

Adjust these helper methods, so that they simply return the content image of the text indicator.
Note that we just use the text indicator itself for the targeted preview anyways, so this image is
effectively unused. In a future patch, we should refactor `DragController` to not bail if the drag
image's `image` is `nullptr` (but the `DragImage` is instead backed by a `TextIndicator`), which
would allow us to avoid some of this extra work.

(WebCore::cascadeForSystemFont): Deleted.
* Source/WebCore/platform/win/DragImageWin.cpp:
(WebCore::createDragImageFromImage):
* Source/WebCore/platform/win/cairo/DragImageWinCairo.cpp:
(WebCore::createDragImageFromImage):

Canonical link: https://commits.webkit.org/289740@main

6270ff4

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	❌ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	❌ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash d959b13)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	🛠 mac	🛠 wpe	🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	❌ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 win-tests
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	🧪 api-wpe
	🧪 ios-wk2-wpt	🧪 mac-wk1	🛠 wpe-cairo
	🧪 api-ios	🧪 mac-wk2	🛠 gtk
	✅ 🛠 vision	❌ 🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 vision-sim	🧪 mac-wk2-stress	🧪 api-gtk
	🧪 vision-wk2	🧪 mac-intel-wk2	🛠 playstation
	❌ 🛠 tv	🛠 mac-safer-cpp
	❌ 🛠 tv-sim
	🛠 watch
	❌ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 38dbd53)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 win-tests
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	🧪 api-wpe
	🧪 ios-wk2-wpt	🧪 mac-wk1	🛠 wpe-cairo
	🧪 api-ios	🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 vision-sim	🧪 mac-wk2-stress	🧪 api-gtk
	🧪 vision-wk2	🧪 mac-intel-wk2	🛠 playstation
	✅ 🛠 tv	🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 0405f3b)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	❌ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 6270ff4)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	❌ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	❌ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[whsieh]

(macOS failures are unrelated)

[whsieh]

Thanks for the review!

[webkit-commit-queue]

Committed 289740@main (75ce30b): https://commits.webkit.org/289740@main

Reviewed commits have been landed. Closing PR #39867 and removing active labels.