Fix build bustage by removing unneeded #include of file that was just removed.

webshell/tests/viewer/nsBrowserWindow.cpp

@@ -81,7 +81,6 @@
 #include "nsCWebBrowser.h"
 
 #include "nsIParser.h"
-#include "nsHTMLContentSinkStream.h"
 #include "nsEditorMode.h"
 
 // Needed for "Find" GUI

webshell/tests/viewer/nsXPBaseWindow.cpp

@@ -50,7 +50,6 @@
 #include "nsIContentViewer.h"
 #include "nsIPresShell.h"
 #include "nsIDocument.h"
-#include "nsHTMLContentSinkStream.h"
 #include "nsIDocument.h"
 #include "nsIDOMEventReceiver.h"
 #include "nsIDOMElement.h"