Enable srcset support in HTMLImageElement

Source/core/html/parser/HTMLPreloadScanner.h

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2010 Google 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 26 matching lines @@
 
 typedef size_t TokenPreloadScannerCheckpoint;
 
 class HTMLParserOptions;
 class HTMLTokenizer;
 class SegmentedString;
 
 class TokenPreloadScanner {
     WTF_MAKE_NONCOPYABLE(TokenPreloadScanner); WTF_MAKE_FAST_ALLOCATED;
 public:
-    explicit TokenPreloadScanner(const KURL& documentURL);
+    explicit TokenPreloadScanner(const KURL& documentURL, float deviceScaleFactor);

[abarth-chromium, 2013/09/19 18:09:52]

No need for |explicit| now that we have more than one parameter.

     ~TokenPreloadScanner();
 
     void scan(const HTMLToken&, const SegmentedString&, PreloadRequestStream& requests);
     void scan(const CompactHTMLToken&, const SegmentedString&, PreloadRequestStream& requests);
 
     void setPredictedBaseElementURL(const KURL& url) { m_predictedBaseElementURL = url; }
 
     // A TokenPreloadScannerCheckpoint is valid until the next call to rewindTo,
     // at which point all outstanding checkpoints are invalidated.
     TokenPreloadScannerCheckpoint createCheckpoint();
@@ skipping 24 matching lines @@
 
         KURL predictedBaseElementURL;
         bool inStyle;
         size_t templateCount;
     };
 
     CSSPreloadScanner m_cssScanner;
     const KURL m_documentURL;
     KURL m_predictedBaseElementURL;
     bool m_inStyle;
+    float m_deviceScaleFactor;
     size_t m_templateCount;
 
     Vector<Checkpoint> m_checkpoints;
 };
 
 class HTMLPreloadScanner {
     WTF_MAKE_NONCOPYABLE(HTMLPreloadScanner); WTF_MAKE_FAST_ALLOCATED;
 public:
-    HTMLPreloadScanner(const HTMLParserOptions&, const KURL& documentURL);
+    HTMLPreloadScanner(const HTMLParserOptions&, const KURL& documentURL, float deviceScaleFactor);
     ~HTMLPreloadScanner();
 
     void appendToEnd(const SegmentedString&);
     void scan(HTMLResourcePreloader*, const KURL& documentBaseElementURL);
 
 private:
     TokenPreloadScanner m_scanner;
     SegmentedString m_source;
     HTMLToken m_token;
     OwnPtr<HTMLTokenizer> m_tokenizer;
 };
 
 }
 
 #endif