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

Source/core/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 99 matching lines @@
 class HTMLCollection;
 class HTMLDialogElement;
 class HTMLDocument;
 class HTMLElement;
 class HTMLFrameOwnerElement;
 class HTMLHeadElement;
 class HTMLIFrameElement;
 class HTMLImport;
 class HTMLImportLoader;
 class HTMLImportsController;
+class HTMLLinkElement;
 class HTMLMapElement;
 class HTMLNameCollection;
 class HTMLScriptElement;
 class HitTestRequest;
 class HitTestResult;
 class IntPoint;
 class JSNode;
 class LayoutPoint;
 class LayoutRect;
 class LiveNodeListBase;
@@ skipping 177 matching lines @@
     void setDoctype(PassRefPtr<DocumentType>);
     DocumentType* doctype() const { return m_docType.get(); }
 
     DOMImplementation& implementation();
 
     Element* documentElement() const
     {
         return m_documentElement.get();
     }
 
-    bool hasManifest() const;
+    // Returns whether the Document has an AppCache manifest.
+    bool hasAppCacheManifest() const;
 
     Location* location() const;
 
     PassRefPtr<Element> createElement(const AtomicString& name, ExceptionState&);
     PassRefPtr<DocumentFragment> createDocumentFragment();
     PassRefPtr<Text> createTextNode(const String& data);
     PassRefPtr<Comment> createComment(const String& data);
     PassRefPtr<CDATASection> createCDATASection(const String& data, ExceptionState&);
     PassRefPtr<ProcessingInstruction> createProcessingInstruction(const String& target, const String& data, ExceptionState&);
     PassRefPtr<Attr> createAttribute(const AtomicString& name, ExceptionState&);
@@ skipping 458 matching lines @@
     // is invalid.  It also sets ExceptionCode when name is invalid.
     static bool parseQualifiedName(const AtomicString& qualifiedName, AtomicString& prefix, AtomicString& localName, ExceptionState&);
 
     // Checks to make sure prefix and namespace do not conflict (per DOM Core 3)
     static bool hasValidNamespaceForElements(const QualifiedName&);
     static bool hasValidNamespaceForAttributes(const QualifiedName&);
 
     HTMLElement* body() const;
     void setBody(PassRefPtr<HTMLElement>, ExceptionState&);
 
-    HTMLHeadElement* head();
+    HTMLHeadElement* head() const;
 
     // Decide which element is to define the viewport's overflow policy. If |rootStyle| is set, use
     // that as the style for the root element, rather than obtaining it on our own. The reason for
     // this is that style may not have been associated with the elements yet - in which case it may
     // have been calculated on the fly (without associating it with the actual element) somewhere.
     Element* viewportDefiningElement(RenderStyle* rootStyle = 0) const;
 
     DocumentMarkerController& markers() const { return *m_markers; }
 
     bool directionSetOnDocumentElement() const { return m_directionSetOnDocumentElement; }
@@ skipping 40 matching lines @@
 
     enum PendingSheetLayout { NoLayoutWithPendingSheets, DidLayoutWithPendingSheets, IgnoreLayoutWithPendingSheets };
 
     bool didLayoutWithPendingStylesheets() const { return m_pendingSheetLayout == DidLayoutWithPendingSheets; }
 
     bool hasNodesWithPlaceholderStyle() const { return m_hasNodesWithPlaceholderStyle; }
     void setHasNodesWithPlaceholderStyle() { m_hasNodesWithPlaceholderStyle = true; }
 
     Vector<IconURL> iconURLs(int iconTypesMask);
 
+    // Returns the HTMLLinkElement currently in use for the Web Manifest.
+    // Returns null if there is no such element.
+    HTMLLinkElement* linkManifest() const;
+
     void setUseSecureKeyboardEntryWhenActive(bool);
     bool useSecureKeyboardEntryWhenActive() const;
 
     void updateFocusAppearanceSoon(bool restorePreviousSelection);
     void cancelFocusAppearanceUpdate();
 
     // Extension for manipulating canvas drawing contexts for use in CSS
     void getCSSCanvasContext(const String& type, const String& name, int width, int height, bool&, RefPtrWillBeRawPtr<CanvasRenderingContext2D>&, bool&, RefPtrWillBeRawPtr<WebGLRenderingContext>&);
     HTMLCanvasElement& getCSSCanvasElement(const String& name);
 
@@ skipping 580 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == document();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h