Adding Link header support for dns-prefetch

Source/core/loader/LinkLoader.cpp

Index: Source/core/loader/LinkLoader.cpp
diff --git a/Source/core/loader/LinkLoader.cpp b/Source/core/loader/LinkLoader.cpp
index 3a928f86edaef55ee6664c857ebe889ae7ba490d..78c2e5a1038fb6d8a0033ccb617d17d433761c1e 100644
--- a/Source/core/loader/LinkLoader.cpp
+++ b/Source/core/loader/LinkLoader.cpp
@@ -113,7 +113,7 @@ void LinkLoader::didSendDOMContentLoadedForPrerender()
     m_client->didSendDOMContentLoadedForLinkPrerender();
 }
 
-bool LinkLoader::loadLink(const LinkRelAttribute& relAttribute, const AtomicString& crossOriginMode, const String& type, const KURL& href, Document& document)
+static void dnsPrefetchIfNeeded(const LinkRelAttribute& relAttribute, const KURL& href, Document& document)
 {
     if (relAttribute.isDNSPrefetch()) {
         Settings* settings = document.settings();
@@ -125,6 +125,26 @@ bool LinkLoader::loadLink(const LinkRelAttribute& relAttribute, const AtomicStri
             prefetchDNS(href.host());
         }
     }
+}
+
+bool LinkLoader::loadLinkFromHeader(const String& headerValue, Document* document)
+{
+    if (!document)
+        return false;
+    LinkHeader header(headerValue);
+    if (!header.valid() || header.url().isEmpty() || header.rel().isEmpty())
+        return false;
+    LinkRelAttribute relAttribute(header.rel());

[Mike West, 2015/02/06 12:22:06]

Can you add a test (or FIXME) for multiple link headers, separated by ','? I
don't think you're handling it yet.

+    KURL url = document->completeURL(header.url());
+    dnsPrefetchIfNeeded(relAttribute, url, *document);
+
+    // FIXME: Add more supported headers as needed.
+    return true;
+}
+
+bool LinkLoader::loadLink(const LinkRelAttribute& relAttribute, const AtomicString& crossOriginMode, const String& type, const KURL& href, Document& document)
+{
+    dnsPrefetchIfNeeded(relAttribute, href, document);
 
     if (relAttribute.isPreconnect() && href.isValid()) {
         preconnect(href);