Expand comment for shouldUseCredentialStorage stub, explaining what it might...

webkit/glue/webframeloaderclient_impl.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 
@@ skipping 193 matching lines @@
   if (d) {
     WebRequestImpl webreq(request);
     d->WillSendRequest(webview, identifier, &webreq);
     request = webreq.frame_load_request().resourceRequest();
   }
 }
 
 bool WebFrameLoaderClient::shouldUseCredentialStorage(DocumentLoader*,
     unsigned long identifier) {
   // FIXME
-  // Intended to call a method on the resource load delegate.
-  // Returns true for backward compatibility.
+  // Intended to pass through to a method on the resource load delegate.
+  // If implemented, that method controls whether the browser should ask the
+  // networking layer for a stored default credential for the page (say from
+  // the Mac OS keychain). If the method returns false, the user should be
+  // presented with an authentication challenge whether or not the networking
+  // layer has a credential stored.
+  // This returns true for backward compatibility: the ability to override the
+  // system credential store is new. (Actually, not yet fully implemented in
+  // WebKit, as of this writing.)
   return true;   
 }
 
-
 void WebFrameLoaderClient::dispatchDidReceiveAuthenticationChallenge(
     DocumentLoader*, unsigned long identifier, const AuthenticationChallenge&) {
   // FIXME
 }
 
 void WebFrameLoaderClient::dispatchDidCancelAuthenticationChallenge(
     DocumentLoader*, unsigned long identifier, const AuthenticationChallenge&) {
   // FIXME
 }
 
@@ skipping 1263 matching lines @@
   if (!middle_or_ctrl && !shift && !alt)
     return false;
 
   DCHECK(disposition);
   if (middle_or_ctrl)
     *disposition = shift ? NEW_FOREGROUND_TAB : NEW_BACKGROUND_TAB;
   else
     *disposition = shift ? NEW_WINDOW : SAVE_TO_DISK;
   return true;
 }