HTML Imports: Teach preloader about HTML Imports.

Source/core/html/parser/HTMLResourcePreloader.cpp

Index: Source/core/html/parser/HTMLResourcePreloader.cpp
diff --git a/Source/core/html/parser/HTMLResourcePreloader.cpp b/Source/core/html/parser/HTMLResourcePreloader.cpp
index 768576271412324d8be479b122f610df86ef2abf..e712dc1383f656f04f83b5c0d2078e824f7fecf6 100644
--- a/Source/core/html/parser/HTMLResourcePreloader.cpp
+++ b/Source/core/html/parser/HTMLResourcePreloader.cpp
@@ -56,6 +56,13 @@ FetchRequest PreloadRequest::resourceRequest(Document* document)
     initiatorInfo.position = m_initiatorPosition;
     FetchRequest request(ResourceRequest(completeURL(document)), initiatorInfo);
 
+    if (m_resourceType == Resource::ImportResource) {
+        bool sameOrigin = document->contextDocument()->securityOrigin()->canRequest(request.url());
+        request.setCrossOriginAccessControl(document->contextDocument()->securityOrigin(),
+            sameOrigin ? AllowStoredCredentials : DoNotAllowStoredCredentials,
+            ClientDidNotRequestCredentials);
+    }
+
     if (m_isCORSEnabled)
         request.setCrossOriginAccessControl(document->securityOrigin(), m_allowCredentials);
     return request;