REGRESSION(258484@main): StreamClientConnection sends destination id in wrong format

[kkinnunen-apple]

ce70a7f

REGRESSION(258484@main): StreamClientConnection sends destination id in wrong format
https://bugs.webkit.org/show_bug.cgi?id=250386
rdar://104076868

Reviewed by Alex Christensen.

258484@main would change the IPC message destination ID to UInt128.
The commit changed also stream IPC destinations as UInt128.

Stream{Client,Server}Connection public API has only ObjectIdentifier<T> instances
as the destination ID. These are uint64_t. Thus sending UInt128 when the
input is only uint64_t is redundant.

Revert back to uint64_t. The stream IPC memory format expects certain layout and alignment
for messages and their fields. The UInt128 change didn't contain these.

It is better to make the 128 bit change in isolation, should the need arise. Given
that 64 bits is relatively big id space, try to preserve the perf benefit of using
this smaller space until needed.

* Source/WebKit/Platform/IPC/StreamClientConnection.h:
(IPC::StreamClientConnection::trySendDestinationIDIfNeeded):
* Source/WebKit/Platform/IPC/StreamServerConnection.cpp:
(IPC::StreamServerConnection::startReceivingMessages):
(IPC::StreamServerConnection::stopReceivingMessages):
(IPC::StreamServerConnection::processSetStreamDestinationID):
* Source/WebKit/Platform/IPC/StreamServerConnection.h:
* Source/WebKit/WebProcess/WebPage/IPCTestingAPI.cpp:
(WebKit::IPCTestingAPI::JSIPCStreamClientConnection::prepareToSendOutOfStreamMessage):

Canonical link: https://commits.webkit.org/258782@main

7ec77d5

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[webkit-early-warning-system]

EWS run on previous version of this PR (hash c57abdb)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	❌ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	❌ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 7ec77d5)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	✅ 🧪 gtk-wk2
	🧪 api-ios	✅ 🧪 mac-wk1	🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 258782@main (ce70a7f): https://commits.webkit.org/258782@main

Reviewed commits have been landed. Closing PR #8465 and removing active labels.