[Cocoa] Fix warnings in WebKitSwift
<rdar://problem/115260515>
Pull request: https://github.com/WebKit/WebKit/pull/17637
Committed 267853@main (b40a8604e4eb): <https://commits.webkit.org/267853@main> Reviewed commits have been landed. Closing PR #17637 and removing active labels.
Re-opened since this is blocked by bug 261413
Pull request: https://github.com/WebKit/WebKit/pull/17706
Committed 267921@main (849790f00ff0): <https://commits.webkit.org/267921@main> Reviewed commits have been landed. Closing PR #17706 and removing active labels.
Committed 267815.579@safari-7617-branch (8d60b5b0fc0b): <https://commits.webkit.org/267815.579@safari-7617-branch> Reviewed commits have been landed. Closing PR #935 and removing active labels.