NTP: Prevent tab sync icons from being cached.

chrome/browser/ui/webui/session_favicon_source.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/webui/session_favicon_source.h"
 
 #include "chrome/browser/sync/glue/session_model_associator.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/common/url_constants.h"
@@ skipping 31 matching lines @@
 
 std::string SessionFaviconSource::GetMimeType(const std::string&) const {
   return "image/png";
 }
 
 bool SessionFaviconSource::ShouldReplaceExistingSource() const {
   // Leave the existing DataSource in place, otherwise we'll drop any pending
   // requests on the floor.
   return false;
 }
+
+bool SessionFaviconSource::AllowCaching() const {
+  // Prevent responses from being cached, otherwise session favicons won't
+  // update in a timely manner.
+  return false;
+}