service worker: Add NavigationPreload runtime flag and skeleton interface

third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.cpp

 // Copyright 2014 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 "modules/serviceworkers/ServiceWorkerRegistration.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/DOMException.h"
@@ skipping 56 matching lines @@
     ASSERT(existingRegistration->getExecutionContext() == executionContext);
     return existingRegistration;
   }
 
   ServiceWorkerRegistration* newRegistration =
       new ServiceWorkerRegistration(executionContext, std::move(handle));
   newRegistration->suspendIfNeeded();
   return newRegistration;
 }
 
+NavigationPreloadManager* ServiceWorkerRegistration::navigationPreload() {
+  if (!m_navigationPreload)
+    m_navigationPreload = NavigationPreloadManager::create();
+  return m_navigationPreload;
+}
+
 String ServiceWorkerRegistration::scope() const {
   return m_handle->registration()->scope().string();
 }
 
 ScriptPromise ServiceWorkerRegistration::update(ScriptState* scriptState) {
   ServiceWorkerContainerClient* client =
       ServiceWorkerContainerClient::from(getExecutionContext());
   if (!client || !client->provider())
     return ScriptPromise::rejectWithDOMException(
         scriptState,
@@ skipping 48 matching lines @@
 void ServiceWorkerRegistration::dispose() {
   // Promptly clears a raw reference from content/ to an on-heap object
   // so that content/ doesn't access it in a lazy sweeping phase.
   m_handle.reset();
 }
 
 DEFINE_TRACE(ServiceWorkerRegistration) {
   visitor->trace(m_installing);
   visitor->trace(m_waiting);
   visitor->trace(m_active);
+  visitor->trace(m_navigationPreload);
   EventTargetWithInlineData::trace(visitor);
   ActiveDOMObject::trace(visitor);
   Supplementable<ServiceWorkerRegistration>::trace(visitor);
 }
 
 void ServiceWorkerRegistration::contextDestroyed() {
   if (m_stopped)
     return;
   m_stopped = true;
   m_handle->registration()->proxyStopped();
 }
 
 }  // namespace blink