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 302 matching lines @@
         exceptionState.throwDOMException(InvalidAccessError, "Must supply document to check");
         return 0;
     }
 
     return doc->layoutView()->hitTestCount();
 }
 
 
 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(document->completeURL(url));
 }
 
 bool Internals::isLoadingFromMemoryCache(const String& url)
 {
     if (!contextDocument())
         return false;
     const String cacheIdentifier = contextDocument()->fetcher()->getCacheIdentifier();
     Resource* resource = memoryCache()->resourceForURL(contextDocument()->completeURL(url), cacheIdentifier);
     return resource && resource->status() == Resource::Cached;
@@ skipping 2047 matching lines @@
 
 ClientRectList* Internals::focusRingRects(Element* element)
 {
     Vector<LayoutRect> rects;
     if (element && element->layoutObject())
         element->layoutObject()->addFocusRingRects(rects, LayoutPoint());
     return ClientRectList::create(rects);
 }
 
 } // namespace blink