--- a/mailnews/base/util/nsMsgProtocol.cpp
+++ b/mailnews/base/util/nsMsgProtocol.cpp
@@ -669,16 +669,22 @@ NS_IMETHODIMP nsMsgProtocol::GetContentC
 }
 
 NS_IMETHODIMP nsMsgProtocol::SetContentCharset(const nsACString &aContentCharset)
 {
   NS_WARNING("nsMsgProtocol::SetContentCharset() not implemented");
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+NS_IMETHODIMP nsMsgProtocol::GetContentDisposition(nsACString &aContentDisposition)
+{
+  aContentDisposition.Truncate();
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsMsgProtocol::GetContentLength(PRInt64 *aContentLength)
 {
   *aContentLength = mContentLength;
   return NS_OK;
 }
 
 NS_IMETHODIMP nsMsgProtocol::SetContentLength(PRInt64 aContentLength)
 {

--- a/mailnews/imap/src/nsImapProtocol.cpp
+++ b/mailnews/imap/src/nsImapProtocol.cpp
@@ -9238,16 +9238,22 @@ NS_IMETHODIMP nsImapMockChannel::GetCont
 }
 
 NS_IMETHODIMP nsImapMockChannel::SetContentCharset(const nsACString &aContentCharset)
 {
   NS_WARNING("nsImapMockChannel::SetContentCharset() not implemented");
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+NS_IMETHODIMP nsImapMockChannel::GetContentDisposition(nsACString &aContentDisposition)
+{
+  aContentDisposition.Truncate();
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsImapMockChannel::GetContentLength(PRInt64 * aContentLength)
 {
   *aContentLength = mContentLength;
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsImapMockChannel::SetContentLength(PRInt64 aContentLength)

--- a/mailnews/news/src/nsNntpMockChannel.cpp
+++ b/mailnews/news/src/nsNntpMockChannel.cpp
@@ -230,16 +230,22 @@ NS_IMETHODIMP nsNntpMockChannel::GetCont
 
 NS_IMETHODIMP nsNntpMockChannel::SetContentCharset(const nsACString &aCharset)
 {
   FORWARD_CALL(SetContentCharset, aCharset)
   m_contentCharset = aCharset;
   return NS_OK;
 }
 
+NS_IMETHODIMP nsNntpMockChannel::GetContentDisposition(nsACString &aContentDisposition)
+{
+  aContentDisposition.Truncate();
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsNntpMockChannel::GetContentLength(PRInt64 *length)
 {
   FORWARD_CALL(GetContentLength, length)
   *length = m_contentLength;
   return NS_OK;
 }
 
 NS_IMETHODIMP