Bug 312527 – [Site Isolation] Route popup menu value-changed IPC to the originating frame

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[zak ridouh]

When a <select> popup menu is open, focus can move to a remote frame during
the popup's nested run loop. WebPageProxy::Internals::valueChangedForPopupMenu()
previously called focusedOrMainFrame() to find the destination process for the
DidChangeSelectedIndexForActivePopupMenu IPC. 

With site isolation, that may resolve to a different process than the one that hosts the <select>, so the
selection change is delivered to the wrong process. The originating WebProcess
never receives the close signal, leaving its m_popupIsVisible state stuck and
making the <select> appear broken, the next click is interpreted as a dismiss
rather than an open, and the chosen option never reaches the DOM.

Capture the originating frame's identifier in m_activePopupMenuFrameID at
showPopupMenu() time and use it to route both DidChangeSelectedIndexForActivePopupMenu
and (on non-Cocoa platforms) SetTextForActivePopupMenu. Clear the identifier in
hidePopupMenu() and resetState().

[zak ridouh]

<rdar://174886701>

[zak ridouh]

Pull request: https://github.com/WebKit/WebKit/pull/62939

[EWS]

Committed 313449@main (0a6b5cd60b4f): <https://commits.webkit.org/313449@main>

Reviewed commits have been landed. Closing PR #62939 and removing active labels.