A sizes attribute parser

Source/core/css/MediaValues.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/css/MediaValues.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/FrameHost.h"
@@ skipping 175 matching lines @@
         mediaValues->m_printMediaType = calculatePrintMediaType(frame),
         mediaValues->m_strictMode = calculateStrictMode(frame);
 
         mediaValues->m_style.clear();
         mediaValues->m_frame = 0;
     }
 
     return mediaValues;
 }
 
-PassRefPtr<MediaValues> MediaValues::create(Document* document, MediaValuesMode mode)
+PassRefPtr<MediaValues> MediaValues::create(const Document& document, MediaValuesMode mode)
 {
-    ASSERT(document);
-    Document* executingDocument = document->import() ? document->import()->master() : document;
+    const Document* executingDocument = document.import() ? document.import()->master() : &document;

[eseidel, 2014/04/08 06:02:14]

const pointers to ref-counted objects rarely make sense given that ref() is
non-const.

     ASSERT(executingDocument->frame());
     ASSERT(executingDocument->renderer());
     ASSERT(executingDocument->renderer()->style());
     LocalFrame* frame = executingDocument->frame();
     RenderStyle* style = executingDocument->renderer()->style();
 
     return MediaValues::create(frame, style, mode);
 }
 
 PassRefPtr<MediaValues> MediaValues::copy() const
@@ skipping 122 matching lines @@
 }
 
 Document* MediaValues::document() const
 {
     if (!m_frame)
         return 0;
     return m_frame->document();
 }
 
 } // namespace