The nsIHTTPHeaderListener interface allows plugin authors to
 access HTTP Response headers after issuing an
 nsIPluginManager::{GetURL,PostURL}() call. <P>

 IMPORTANT NOTE: The plugin author must provide an instance to
 {GetURL,PostURL}() that implements both nsIPluginStreamListener and
 nsIHTTPHeaderListener.  This instance is passed in through
 {GetURL,PostURL}()'s streamListener parameter.  The browser will then
 QI thi streamListener to see if it implements
 nsIHTTPHeaderListener.
[scriptable, uuid(ea51e0b8-871c-4b85-92da-6f400394c5ec)]
interface nsIHTTPHeaderListener : nsISupports

Methods

 Called for each HTTP Response header.
 NOTE: You must copy the values of the params.
void newResponseHeader(in string headerName, in string headerValue) 
 Called once for the HTTP Response status line.
 Value does NOT include a terminating newline.
 NOTE: You must copy this value.
void statusLine(in string line)