Make ClientHintsPreferences class work like a class.

Source/core/loader/HttpEquiv.cpp

Index: Source/core/loader/HttpEquiv.cpp
diff --git a/Source/core/loader/HttpEquiv.cpp b/Source/core/loader/HttpEquiv.cpp
index 1e387226f9115bb3a2ddfe62e74a62b0b22e01bf..4891b71d4c420cd41522d21d1de5cce2f45fa20f 100644
--- a/Source/core/loader/HttpEquiv.cpp
+++ b/Source/core/loader/HttpEquiv.cpp
@@ -62,9 +62,7 @@ void HttpEquiv::processHttpEquivAcceptCH(Document& document, const AtomicString&
         return;
 
     UseCounter::count(document, UseCounter::ClientHintsMetaAcceptCH);
-    ClientHintsPreferences clientHintsPreferences = document.clientHintsPreferences();
-    handleAcceptClientHintsHeader(content, clientHintsPreferences, document.fetcher());
-    document.setClientHintsPreferences(clientHintsPreferences);
+    document.clientHintsPreferences().updateFromAcceptClientHintsHeader(content, document.fetcher());
 }
 
 void HttpEquiv::processHttpEquivDefaultStyle(Document& document, const AtomicString& content)