HTML Imports: Teach preloader about HTML Imports.

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple 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.
@@ skipping 278 matching lines @@
 
     bool isPartial;
     unsigned needsLayoutObjects;
     unsigned totalObjects;
     contextFrame->countObjectsNeedingLayout(needsLayoutObjects, totalObjects, isPartial);
     return needsLayoutObjects;
 }
 
 bool Internals::isPreloaded(const String& url)
 {
-    Document* document = contextDocument();
+    return isPreloadedBy(url, contextDocument());
+}
+
+bool Internals::isPreloadedBy(const String& url, Document* document)
+{
+    if (!document)
+        return false;
     return document->fetcher()->isPreloaded(url);
 }
 
 bool Internals::isLoadingFromMemoryCache(const String& url)
 {
     if (!contextDocument())
         return false;
     Resource* resource = memoryCache()->resourceForURL(contextDocument()->completeURL(url));
     return resource && resource->status() == Resource::Cached;
 }
@@ skipping 2061 matching lines @@
 String Internals::textSurroundingNode(Node* node, int x, int y, unsigned long maxLength)
 {
     if (!node)
         return String();
     blink::WebPoint point(x, y);
     SurroundingText surroundingText(VisiblePosition(node->renderer()->positionForPoint(static_cast<IntPoint>(point))), maxLength);
     return surroundingText.content();
 }
 
 }