Add a feature flag for supporting partitioned cookies

[sysrqb]

72e1a8685ace439f1209f8f449e73069a2398c89

Add a feature flag for supporting partitioned cookies
https://bugs.webkit.org/show_bug.cgi?id=279547
rdar://problem/135829408

Reviewed by NOBODY (OOPS!).

This patch adds a new preference and propagates preferences changes to the
Network process whenever a page is created or destroyed. This extends the
behavior we currently use for updating Blob URL partitioning state. This patch
doesn't introduce any changes in the current behavior.

* Source/WTF/Scripts/Preferences/UnifiedWebPreferences.yaml:
* Source/WebCore/platform/network/NetworkStorageSession.cpp:
(WebCore::NetworkStorageSession::setOptInCookiePartitioningEnabled):
* Source/WebCore/platform/network/NetworkStorageSession.h:
(WebCore::NetworkStorageSession::isOptInCookiePartitioningEnabled const):
* Source/WebKit/NetworkProcess/NetworkProcess.cpp:
(WebKit::NetworkProcess::setOptInCookiePartitioningEnabled const):
* Source/WebKit/NetworkProcess/NetworkProcess.h:
* Source/WebKit/NetworkProcess/NetworkProcess.messages.in:
* Source/WebKit/NetworkProcess/NetworkSession.cpp:
(WebKit::NetworkSession::setOptInCookiePartitioningEnabled):
* Source/WebKit/NetworkProcess/NetworkSession.h:
* Source/WebKit/NetworkProcess/NetworkSessionCreationParameters.h:
* Source/WebKit/NetworkProcess/NetworkSessionCreationParameters.serialization.in:
* Source/WebKit/UIProcess/WebProcessProxy.cpp:
(WebKit::WebProcessProxy::addExistingWebPage):
(WebKit::WebProcessProxy::removeWebPage):
* Source/WebKit/UIProcess/WebsiteData/WebsiteDataStore.cpp:
(WebKit::WebsiteDataStore::isOptInCookiePartitioningEnabled const):
(WebKit::WebsiteDataStore::propagateSettingUpdatesToNetworkProcess):
(WebKit::WebsiteDataStore::parameters):
(WebKit::WebsiteDataStore::updateBlobRegistryPartitioningState): Deleted.
* Source/WebKit/UIProcess/WebsiteData/WebsiteDataStore.h:

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✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2	✅ 🧪 wincairo-tests
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🧪 api-mac	🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	❌ 🧪 mac-wk1	✅ 🛠 wpe-cairo
🛠 🧪 jsc	🧪 api-ios	❌ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	🛠 tv		✅ 🧪 jsc-armv7-tests
	✅ 🛠 tv-sim
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✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	❌ 🧪 wpe-wk2	✅ 🧪 wincairo-tests
✅ 🧪 webkitperl	❌ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	❌ 🧪 mac-wk1	✅ 🛠 wpe-cairo
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	❌ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	❌ 🧪 mac-AS-debug-wk2	❌ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	❌ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	🛠 tv		❌ 🧪 jsc-armv7-tests
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 2f7cc78)

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	❌ 🛠 ios	❌ 🛠 mac	🛠 wpe	🛠 wincairo
	❌ 🛠 ios-sim	❌ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 wincairo-tests
✅ 🧪 webkitperl	❌ 🧪 ios-wk2	❌ 🧪 api-mac	🧪 api-wpe
	❌ 🧪 ios-wk2-wpt	❌ 🧪 mac-wk1	🛠 wpe-cairo
🛠 🧪 jsc	❌ 🧪 api-ios	❌ 🧪 mac-wk2	🛠 gtk
✅ 🛠 🧪 jsc-arm64	🛠 vision	❌ 🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	❌ 🛠 vision-sim	❌ 🧪 mac-wk2-stress	🧪 api-gtk
	⏳ 🧪 vision-wk2	❌ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	🛠 tv		🧪 jsc-armv7-tests
	❌ 🛠 tv-sim
	❌ 🛠 watch
	🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 13460af)

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 wincairo-tests
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🧪 api-mac	⏳ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	🧪 mac-wk1	✅ 🛠 wpe-cairo
🛠 🧪 jsc	⏳ 🧪 api-ios	🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	🧪 api-gtk
	✅ 🧪 vision-wk2	🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	🛠 tv		🧪 jsc-armv7-tests
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 888fd47)

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 wincairo-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv		🧪 jsc-armv7-tests
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim