Add <link rel=preconnect> support to the HTMLPreloadScanner

Source/core/html/parser/HTMLResourcePreloader.cpp

 /*
  * Copyright (C) 2013 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/html/parser/HTMLResourcePreloader.h"
 
 #include "core/dom/Document.h"
 #include "core/fetch/FetchInitiatorInfo.h"
 #include "core/fetch/ResourceFetcher.h"
+#include "platform/network/NetworkHints.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 inline HTMLResourcePreloader::HTMLResourcePreloader(Document& document)
     : m_document(document)
 {
 }
 
 PassOwnPtrWillBeRawPtr<HTMLResourcePreloader> HTMLResourcePreloader::create(Document& document)
 {
     return adoptPtrWillBeNoop(new HTMLResourcePreloader(document));
 }
 
 DEFINE_TRACE(HTMLResourcePreloader)
 {
     visitor->trace(m_document);
 }
 
+static void preconnectHost(PreloadRequest* request)
+{
+    ASSERT(request);
+    ASSERT(request->isPreconnect());
+    KURL host(request->baseURL(), request->resourceURL());
+    if (!host.isValid() || !host.protocolIsInHTTPFamily())
+        return;
+    CrossOriginAttributeValue crossOrigin = CrossOriginAttributeNotSet;
+    if (request->isCORS()) {
+        if (request->isAllowCredentials())
+            crossOrigin = CrossOriginAttributeUseCredentials;
+        else
+            crossOrigin = CrossOriginAttributeAnonymous;
+    }
+    preconnect(host, crossOrigin);
+}
+
 void HTMLResourcePreloader::preload(PassOwnPtr<PreloadRequest> preload)
 {
+    if (preload->isPreconnect()) {
+        preconnectHost(preload.get());
+        return;
+    }
     FetchRequest request = preload->resourceRequest(m_document);
     Platform::current()->histogramCustomCounts("WebCore.PreloadDelayMs", static_cast<int>(1000 * (monotonicallyIncreasingTime() - preload->discoveryTime())), 0, 2000, 20);
     m_document->fetcher()->preload(preload->resourceType(), request, preload->charset());
 }
 
 } // namespace blink