Enable srcset support in HTMLImageElement

Source/core/html/parser/HTMLDocumentParser.cpp

 /*
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 540 matching lines @@
 
     if (isStopped())
         return;
 
     if (session.needsYield)
         m_parserScheduler->scheduleForResume();
 
     if (isWaitingForScripts()) {
         ASSERT(m_tokenizer->state() == HTMLTokenizer::DataState);
         if (!m_preloadScanner) {
-            m_preloadScanner = adoptPtr(new HTMLPreloadScanner(m_options, document()->url()));
+            float deviceScaleFactor = 1.0;
+            if (Page* page = document()->page())
+                deviceScaleFactor = page->deviceScaleFactor();
+            m_preloadScanner = adoptPtr(new HTMLPreloadScanner(m_options, document()->url(), deviceScaleFactor));
             m_preloadScanner->appendToEnd(m_input.current());
         }
         m_preloadScanner->scan(m_preloader.get(), document()->baseElementURL());
     }
 
     InspectorInstrumentation::didWriteHTML(cookie, m_input.current().currentLine().zeroBasedInt());
 }
 
 void HTMLDocumentParser::constructTreeFromHTMLToken(HTMLToken& rawToken)
 {
@@ skipping 53 matching lines @@
     }
 
     SegmentedString excludedLineNumberSource(source);
     excludedLineNumberSource.setExcludeLineNumbers();
     m_input.insertAtCurrentInsertionPoint(excludedLineNumberSource);
     pumpTokenizerIfPossible(ForceSynchronous);
 
     if (isWaitingForScripts()) {
         // Check the document.write() output with a separate preload scanner as
         // the main scanner can't deal with insertions.
-        if (!m_insertionPreloadScanner)
-            m_insertionPreloadScanner = adoptPtr(new HTMLPreloadScanner(m_options, document()->url()));
+        if (!m_insertionPreloadScanner) {
+            float deviceScaleFactor = 1.0;
+            if (Page* page = document()->page())
+                deviceScaleFactor = page->deviceScaleFactor();
+            m_insertionPreloadScanner = adoptPtr(new HTMLPreloadScanner(m_options, document()->url(), deviceScaleFactor));
+        }
         m_insertionPreloadScanner->appendToEnd(source);
         m_insertionPreloadScanner->scan(m_preloader.get(), document()->baseElementURL());
     }
 
     endIfDelayed();
 }
 
 void HTMLDocumentParser::startBackgroundParser()
 {
     ASSERT(shouldUseThreading());
@@ skipping 304 matching lines @@
         m_parserScheduler->suspend();
 }
 
 void HTMLDocumentParser::resumeScheduledTasks()
 {
     if (m_parserScheduler)
         m_parserScheduler->resume();
 }
 
 }