Implement enough of the Clipboard API to have a working `writeText`.
Testing: Unfortunately many clipboard-apis tests require testdriver, so
only idlharness ones will pass now.
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Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com>
Fixes an oversight of #36097, in which converting to a Promise would
fail if the value passed wasn't actually a Promise, while in binding
code we actually call `Promise::new_resolved` on the value.
Testing: There are wpt tests that should pass now
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Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com>
implement the `ClipboardItem` interface
Testing: covered by existing wpt tests
part of #36084
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Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com>
