Make ClientHintsPreferences class work like a class.

Source/core/loader/HttpEquiv.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "HttpEquiv.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/StyleEngine.h"
 #include "core/fetch/ClientHintsPreferences.h"
@@ skipping 44 matching lines @@
     else
         ASSERT_NOT_REACHED();
 }
 
 void HttpEquiv::processHttpEquivAcceptCH(Document& document, const AtomicString& content)
 {
     if (!document.frame())
         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)
 {
     // The preferred style set has been overridden as per section
     // 14.3.2 of the HTML4.0 specification. We need to update the
     // sheet used variable and then update our style selector.
     // For more info, see the test at:
     // http://www.hixie.ch/tests/evil/css/import/main/preferred.html
     // -dwh
@@ skipping 36 matching lines @@
     // Stopping the loader isn't enough, as we're already parsing the document; to honor the header's
     // intent, we must navigate away from the possibly partially-rendered document to a location that
     // doesn't inherit the parent's SecurityOrigin.
     frame->navigate(document, SecurityOrigin::urlWithUniqueSecurityOrigin(), true, UserGestureStatus::None);
     RefPtrWillBeRawPtr<ConsoleMessage> consoleMessage = ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, message);
     consoleMessage->setRequestIdentifier(requestIdentifier);
     document.addConsoleMessage(consoleMessage.release());
 }
 
 }