Revert of Moved text decoding to the parser thread

Source/core/html/parser/HTMLMetaCharsetParser.h

Index: Source/core/html/parser/HTMLMetaCharsetParser.h
diff --git a/Source/core/html/parser/HTMLMetaCharsetParser.h b/Source/core/html/parser/HTMLMetaCharsetParser.h
index 65d9517a2e0fe8ce0293ba7bb6888665f44fbd98..3393fca40d234bda8b3dbeedb0500c79b37623fc 100644
--- a/Source/core/html/parser/HTMLMetaCharsetParser.h
+++ b/Source/core/html/parser/HTMLMetaCharsetParser.h
@@ -48,10 +48,22 @@ public:
 
     const WTF::TextEncoding& encoding() { return m_encoding; }
 
+    typedef Vector<pair<String, String> > AttributeList;
+    // The returned encoding might not be valid.
+    static WTF::TextEncoding encodingFromMetaAttributes(const AttributeList&
+);
+
 private:
     HTMLMetaCharsetParser();
 
     bool processMeta();
+    static String extractCharset(const String&);
+
+    enum Mode {
+        None,
+        Charset,
+        Pragma,
+    };
 
     OwnPtr<HTMLTokenizer> m_tokenizer;
     OwnPtr<TextCodec> m_assumedCodec;