Set encoding to UTF-8 for HTML Imports if no encoding is specified in the HTTP response

Source/core/html/imports/HTMLImportLoader.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 90 matching lines @@
 
     setState(finishWriting());
 }
 
 HTMLImportLoader::State HTMLImportLoader::startWritingAndParsing(const ResourceResponse& response)
 {
     ASSERT(!m_imports.isEmpty());
     DocumentInit init = DocumentInit(response.url(), 0, m_controller->master()->contextDocument(), m_controller)
         .withRegistrationContext(m_controller->master()->registrationContext());
     m_importedDocument = HTMLDocument::create(init);
-    m_writer = DocumentWriter::create(m_importedDocument.get(), response.mimeType(), response.textEncodingName());
+    m_writer = DocumentWriter::create(m_importedDocument.get(), response.mimeType(), "UTF-8");
 
     return StateLoading;
 }
 
 HTMLImportLoader::State HTMLImportLoader::finishWriting()
 {
     return StateWritten;
 }
 
 HTMLImportLoader::State HTMLImportLoader::finishParsing()
@@ skipping 66 matching lines @@
         client->didFinishLoading();
 }
 
 void HTMLImportLoader::removeImport(HTMLImportChild* client)
 {
     ASSERT(kNotFound != m_imports.find(client));
     m_imports.remove(m_imports.find(client));
 }
 
 } // namespace WebCore