diff --git a/string/src/nsSharedBufferList.cpp b/string/src/nsSharedBufferList.cpp
index 84342e07535d..85fa31b3dfd0 100755
--- a/string/src/nsSharedBufferList.cpp
+++ b/string/src/nsSharedBufferList.cpp
@@ -145,6 +145,13 @@ nsSharedBufferList::UnlinkBuffer( Buffer* aBufferToUnlink )
   }
 
 
+void
+nsSharedBufferList::DiscardSuffix( PRUint32 /* aLengthToDiscard */ )
+  {
+    // XXX
+  }
+
+
 
 #if 0
 template <class CharT>
diff --git a/xpcom/ds/nsSharedBufferList.cpp b/xpcom/ds/nsSharedBufferList.cpp
index 84342e07535d..85fa31b3dfd0 100755
--- a/xpcom/ds/nsSharedBufferList.cpp
+++ b/xpcom/ds/nsSharedBufferList.cpp
@@ -145,6 +145,13 @@ nsSharedBufferList::UnlinkBuffer( Buffer* aBufferToUnlink )
   }
 
 
+void
+nsSharedBufferList::DiscardSuffix( PRUint32 /* aLengthToDiscard */ )
+  {
+    // XXX
+  }
+
+
 
 #if 0
 template <class CharT>
diff --git a/xpcom/string/src/nsSharedBufferList.cpp b/xpcom/string/src/nsSharedBufferList.cpp
index 84342e07535d..85fa31b3dfd0 100755
--- a/xpcom/string/src/nsSharedBufferList.cpp
+++ b/xpcom/string/src/nsSharedBufferList.cpp
@@ -145,6 +145,13 @@ nsSharedBufferList::UnlinkBuffer( Buffer* aBufferToUnlink )
   }
 
 
+void
+nsSharedBufferList::DiscardSuffix( PRUint32 /* aLengthToDiscard */ )
+  {
+    // XXX
+  }
+
+
 
 #if 0
 template <class CharT>