Refactor the viewport code to be more understandable

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 271 matching lines @@
     DEFINE_ATTRIBUTE_EVENT_LISTENER(touchmove);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(touchend);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(touchcancel);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(webkitfullscreenchange);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(webkitfullscreenerror);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(webkitpointerlockchange);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(webkitpointerlockerror);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(webkitvisibilitychange);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(securitypolicyviolation);
 
+    bool shouldOverrideLegacyViewport(ViewportArguments::Type);
     void setViewportArguments(const ViewportArguments&);
     const ViewportArguments& viewportArguments() const { return m_viewportArguments; }
 #ifndef NDEBUG
     bool didDispatchViewportPropertiesChanged() const { return m_didDispatchViewportPropertiesChanged; }
 #endif
     bool hasLegacyViewportTag() const { return m_legacyViewportArguments.isLegacyViewportType(); }
 
     void setReferrerPolicy(ReferrerPolicy referrerPolicy) { m_referrerPolicy = referrerPolicy; }
     ReferrerPolicy referrerPolicy() const { return m_referrerPolicy; }
 
@@ skipping 1095 matching lines @@
 
 inline const Document* Document::templateDocument() const
 {
     // If DOCUMENT does not have a browsing context, Let TEMPLATE CONTENTS OWNER be DOCUMENT and abort these steps.
     if (!m_frame)
         return this;
 
     return m_templateDocument.get();
 }
 
-inline void Document::setViewportArguments(const ViewportArguments& viewportArguments)
+inline bool Document::shouldOverrideLegacyViewport(ViewportArguments::Type origin)
 {
-    // If the legacy viewport tag has higher priority than the cascaded @viewport
-    // descriptors, use the values from the legacy tag.
-    if (viewportArguments.type < m_legacyViewportArguments.type)
-        m_viewportArguments = m_legacyViewportArguments;
-    else
-        m_viewportArguments = viewportArguments;
-    updateViewportArguments();
+    // The different (legacy) meta tags have different priorities based on the type
+    // regardless of which order they appear in the DOM. The priority is given by the
+    // ViewportArguments::Type enum.
+    return origin >= m_legacyViewportArguments.type;
 }
 
 inline Document* toDocument(ScriptExecutionContext* scriptExecutionContext)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!scriptExecutionContext || scriptExecutionContext->isDocument());
     return static_cast<Document*>(scriptExecutionContext);
 }
 
 inline const Document* toDocument(const ScriptExecutionContext* scriptExecutionContext)
 {
@@ skipping 21 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == documentInternal();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h