Delegating the "are images allowed" decision to renderer.

chrome/common/render_messages.cc

 // Copyright (c) 2011 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/common/render_messages.h"
 
 namespace IPC {
 
 void ParamTraits<ContentSettings>::Write(
     Message* m, const ContentSettings& settings) {
   for (size_t i = 0; i < arraysize(settings.settings); ++i)
     WriteParam(m, settings.settings[i]);
 }
 
 bool ParamTraits<ContentSettings>::Read(
     const Message* m, void** iter, ContentSettings* r) {
   for (size_t i = 0; i < arraysize(r->settings); ++i) {
     if (!ReadParam(m, iter, &r->settings[i]))
       return false;
   }
   return true;
 }
 
 void ParamTraits<ContentSettings>::Log(
     const ContentSettings& p, std::string* l) {
   l->append("<ContentSettings>");
 }
 
+void ParamTraits<ContentSettingsPattern>::Write(
+    Message* m, const ContentSettingsPattern& pattern) {
+  WriteParam(m, pattern.ToString());
+}
+
+bool ParamTraits<ContentSettingsPattern>::Read(
+    const Message* m, void** iter, ContentSettingsPattern* r) {
+  std::string s;
+  if (!ReadParam(m, iter, &s))
+    return false;
+  *r = ContentSettingsPattern::FromString(s);
+  return true;
+}
+
+void ParamTraits<ContentSettingsPattern>::Log(
+    const ContentSettingsPattern& p, std::string* l) {
+  l->append("<ContentSettingsPattern>");
+}
+
 }  // namespace IPC