Add support for rel=next to Prerender in Blink.

Source/core/loader/LinkLoader.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 18 matching lines @@
  *
  */
 
 #include "config.h"
 #include "core/loader/LinkLoader.h"
 
 #include "FetchInitiatorTypeNames.h"
 #include "core/dom/Document.h"
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/ResourceFetcher.h"
+#include "core/frame/Settings.h"
 #include "core/html/LinkRelAttribute.h"
 #include "core/loader/PrerenderHandle.h"
-#include "core/frame/Settings.h"
+#include "platform/Prerender.h"
 #include "platform/network/DNS.h"
 
 namespace WebCore {
 
+static unsigned prerenderRelTypesFromRelAttribute(const LinkRelAttribute& relAttribute)
+{
+    unsigned result = 0;
+    if (relAttribute.isLinkPrerender())
+        result |= PrerenderRelTypePrerender;
+    if (relAttribute.isLinkNext())
+        result |= PrerenderRelTypeNext;
+
+    return result;
+}
+
 LinkLoader::LinkLoader(LinkLoaderClient* client)
     : m_client(client)
     , m_linkLoadTimer(this, &LinkLoader::linkLoadTimerFired)
     , m_linkLoadingErrorTimer(this, &LinkLoader::linkLoadingErrorTimerFired)
 {
 }
 
 LinkLoader::~LinkLoader()
 {
 }
@@ skipping 56 matching lines @@
     if ((relAttribute.isLinkPrefetch() || relAttribute.isLinkSubresource()) && href.isValid() && document.frame()) {
         if (!m_client->shouldLoadLink())
             return false;
         Resource::Type type = relAttribute.isLinkSubresource() ?  Resource::LinkSubresource : Resource::LinkPrefetch;
         FetchRequest linkRequest(ResourceRequest(document.completeURL(href)), FetchInitiatorTypeNames::link);
         if (!crossOriginMode.isNull())
             linkRequest.setCrossOriginAccessControl(document.securityOrigin(), crossOriginMode);
         setResource(document.fetcher()->fetchLinkResource(type, linkRequest));
     }
 
-    if (relAttribute.isLinkPrerender()) {
+    if (const unsigned prerenderRelTypes = prerenderRelTypesFromRelAttribute(relAttribute)) {
         if (!m_prerender) {
-            m_prerender = PrerenderHandle::create(document, this, href);
+            m_prerender = PrerenderHandle::create(document, this, href, prerenderRelTypes);
         } else if (m_prerender->url() != href) {
             m_prerender->cancel();
-            m_prerender = PrerenderHandle::create(document, this, href);
+            m_prerender = PrerenderHandle::create(document, this, href, prerenderRelTypes);
         }
+        // TODO(gavinp): Handle changes to rel types of existing prerenders.
     } else if (m_prerender) {
         m_prerender->cancel();
         m_prerender.clear();
     }
     return true;
 }
 
 void LinkLoader::released()
 {
     // Only prerenders need treatment here; other links either use the Resource interface, or are notionally
     // atomic (dns prefetch).
     if (m_prerender) {
         m_prerender->cancel();
         m_prerender.clear();
     }
 }
 
 }