Implement the logic to find the correct <link> for Manifest in Document.

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 2340 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();
 }
 
+HTMLLinkElement* Internals::linkManifest(Document* document, ExceptionState& exceptionState)
+{
+    if (!document) {
+        exceptionState.throwDOMException(InvalidAccessError, "No context document is available.");
+        return 0;
+    }
+
+    return document->linkManifest();
 }

[abarth-chromium, 2014/05/09 03:06:00]

I'd skip adding this function.  We'll probably want to test this feature with a
WebViewTest rather than LayoutTests that poke internals.

+
+}