Bug 318493 – [Site Isolation] Web Inspector: Network domain emulations/headers not forwarded to web process

• Status: RESOLVED
• Resolution: FIXED
• Component: Web Inspector

[Qianlang Chen]

ProxyingNetworkAgent stubs out three Network domain configuration commands without actually applying them. setExtraHTTPHeaders and setResourceCachingDisabled both carry explicit `// FIXME: Forward to all WebContent processes` comments. setEmulatedConditions returns `makeUnexpected("Not supported")` unconditionally

In the non-SI path, InspectorNetworkAgent::setExtraHTTPHeaders populates m_extraRequestHeaders, which willSendRequest applies to every outgoing request (InspectorNetworkAgent.cpp lines 415–416, 771–772). setResourceCachingDisabled calls Page::setResourceCachingDisabledByWebInspector via PageNetworkAgent::setResourceCachingDisabledInternal (PageNetworkAgent.cpp:117). setEmulatedConditions reaches WebsiteDataStore::setEmulatedConditions → NetworkProcess::setEmulatedConditions through the WebInspectorBackendClient → WebInspectorUIProxy chain (WebInspectorUIProxy.cpp:812)

Without these, extra request headers set in the inspector are silently dropped, cache disabling has no effect on cross-origin iframes under SI, and network throttling emulation does nothing

Possible fixes:
(1) For setExtraHTTPHeaders and setResourceCachingDisabled: add new SetExtraHTTPHeaders and SetResourceCachingDisabled IPC messages to WebInspectorBackend.messages.in, handle them in WebInspectorBackend to forward to the page's InspectorNetworkAgent, and implement ProxyingNetworkAgent to fan the messages out via forEachWebContentProcess (matching the existing pattern used by EnableNetworkInstrumentation)
(2) For setEmulatedConditions: since ProxyingNetworkAgent already lives in the UIProcess and has access to WebPageProxy, it can call m_inspectedPage->websiteDataStore().setEmulatedConditions(...) directly — bypassing the WebContent-process hop that the legacy path requires

rdar://181060656

[Qianlang Chen]

Pull Request: https://github.com/WebKit/WebKit/pull/68573

[EWS]

Committed 316819@main (65ee250042a1): <https://commits.webkit.org/316819@main>

Reviewed commits have been landed. Closing PR #68573 and removing active labels.