Refactor MIME type related methods in XHR for readability

Source/core/xml/XMLHttpRequest.h

 /*
  *  Copyright (C) 2003, 2006, 2008 Apple Inc. All rights reserved.
  *  Copyright (C) 2005, 2006 Alexey Proskuryakov <ap@nypop.com>
  *  Copyright (C) 2011 Google Inc. All rights reserved.
  *  Copyright (C) 2012 Intel Corporation
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
@@ skipping 142 matching lines @@
     virtual void didSendData(unsigned long long bytesSent, unsigned long long totalBytesToBeSent) OVERRIDE;
     virtual void didReceiveResponse(unsigned long identifier, const ResourceResponse&) OVERRIDE;
     virtual void didReceiveData(const char* data, int dataLength) OVERRIDE;
     // When responseType is set to "blob", didDownloadData() is called instead
     // of didReceiveData().
     virtual void didDownloadData(int dataLength) OVERRIDE;
     virtual void didFinishLoading(unsigned long identifier, double finishTime) OVERRIDE;
     virtual void didFail(const ResourceError&) OVERRIDE;
     virtual void didFailRedirectCheck() OVERRIDE;
 
-    AtomicString responseMIMEType() const;
+    // Returns the MIME type part of m_mimeTypeOverride if present and
+    // successfully parsed, or returns one of the "Content-Type" header value
+    // of the received response.
+    //
+    // This method is named after the term "final MIME type" defined in the
+    // spec but doesn't convert the result to ASCII lowercase as specified in
+    // the spec. Must be lowered later or compared using case insensitive
+    // comparison functions if required.
+    AtomicString finalResponseMIMEType() const;
+    // The same as finalResponseMIMEType() but fallbacks to "text/xml" if
+    // finalResponseMIMEType() returns an empty string.
+    AtomicString finalResponseMIMETypeWithFallback() const;
     bool responseIsXML() const;
 
     PassOwnPtr<TextResourceDecoder> createDecoder() const;
 
     void initResponseDocument();
     bool areMethodAndURLValidForSend();
 
     bool initSend(ExceptionState&);
     void sendBytesData(const void*, size_t, ExceptionState&);
 
@@ skipping 31 matching lines @@
     // Handles didFail() call for timeout.
     void handleDidTimeout();
 
     void handleRequestError(ExceptionCode, const AtomicString&, long long, long long);
 
     OwnPtrWillBeMember<XMLHttpRequestUpload> m_upload;
 
     KURL m_url;
     AtomicString m_method;
     HTTPHeaderMap m_requestHeaders;
+    // Not converted to ASCII lowercase. Must be lowered later or compared
+    // using case insensitive comparison functions if needed.
     AtomicString m_mimeTypeOverride;
     unsigned long m_timeoutMilliseconds;
     RefPtrWillBeMember<Blob> m_responseBlob;
     RefPtrWillBeMember<Stream> m_responseStream;
 
     RefPtr<ThreadableLoader> m_loader;
     State m_state;
 
     ResourceResponse m_response;
-    String m_responseEncoding;
+    String m_finalResponseCharset;
 
     OwnPtr<TextResourceDecoder> m_decoder;
 
     ScriptString m_responseText;
     RefPtrWillBeMember<Document> m_responseDocument;
 
     RefPtr<SharedBuffer> m_binaryResponseBuilder;
     long long m_downloadedBlobLength;
 
     RefPtr<ArrayBuffer> m_responseArrayBuffer;
@@ skipping 23 matching lines @@
     bool m_parsedResponse;
     bool m_error;
     bool m_uploadEventsAllowed;
     bool m_uploadComplete;
     bool m_sameOriginRequest;
 };
 
 } // namespace blink
 
 #endif // XMLHttpRequest_h