313657 2026-04-29 08:53:22 -0700 [Site Isolation] Enable same-site BFCache with cross-site iframes 2026-05-28 09:40:57 -0700 1 1 1 Unclassified WebKit WebKit Misc. WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 basuke basuke webkit-bug-importer oldest_to_newest 2205799 0 basuke 2026-04-29 08:53:22 -0700 Step 2 of same-site BFCache under Site Isolation. Step 1 (bug 313615) enabled in-process BFCache for same-site navigations when the page has no cross-site iframes. This bug covers the remaining case: pages WITH cross-site iframes. The challenge is that in-process BFCache (driven by FrameLoader in the WebProcess) does not coordinate with iframe processes. Cross-site iframe content lives in separate processes that need to be suspended/restored. Approach: When the WebProcess caches a page with cross-site iframes, it notifies the UIProcess via a new IPC. The UIProcess then calls the existing suspendSubframeProcesses() to coordinate iframe process suspension using the existing SetSubframesSuspended IPC. On restore, the reverse path unsuspends iframe processes. This completes same-site BFCache support under Site Isolation. rdar://175857874 2208122 1 webkit-bug-importer 2026-05-06 08:54:12 -0700 <rdar://problem/176368842> 2210142 2 basuke 2026-05-12 08:36:07 -0700 Pull request: https://github.com/WebKit/WebKit/pull/64762 2215341 3 ews-feeder 2026-05-28 09:40:56 -0700 Committed 314050@main (444bd55f4300): <https://commits.webkit.org/314050@main> Reviewed commits have been landed. Closing PR #64762 and removing active labels.