Linux Mac OSX Windows
 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(8b246748-1dd2-11b2-9512-9dc84a95fc2f)]
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)