b=337451. Fix default charset for SAX parser. r=sicking, sr=peterv

parser/xml/src/Makefile.in

@@ -53,6 +53,7 @@ REQUIRES	= \
 		string \
 		htmlparser \
 		content \
+		uconv \
 		$(NULL)
 
 CPPSRCS		= \

parser/xml/src/nsSAXXMLReader.h

@@ -107,7 +107,10 @@ private:
   nsCOMPtr<nsIStreamListener> mListener;
   nsCOMPtr<nsIRequestObserver> mParserObserver;
   PRBool mIsAsyncParse;
-  nsresult InitParser(nsIRequestObserver *aListener);
+  static PRBool TryChannelCharset(nsIChannel *aChannel,
+                                  PRInt32& aCharsetSource,
+                                  nsACString& aCharset);
+  nsresult InitParser(nsIRequestObserver *aListener, nsIChannel *aChannel);
   nsresult SplitExpatName(const PRUnichar *aExpatName,
                           nsString &aURI,
                           nsString &aLocalName,