Put some plug-ins behind an infobar, where they have:...

chrome/browser/content_settings/host_content_settings_map.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/browser/content_settings/host_content_settings_map.h"
 
 #include "base/command_line.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_thread.h"
@@ skipping 278 matching lines @@
   ContentSettings output = GetNonDefaultContentSettings(url);
 
   // If we require a resource identifier, set the content settings to default,
   // otherwise make the defaults explicit.
   for (int j = 0; j < CONTENT_SETTINGS_NUM_TYPES; ++j) {
     if (RequiresResourceIdentifier(ContentSettingsType(j))) {
       output.settings[j] = CONTENT_SETTING_DEFAULT;
     } else {
       // A managed default content setting has the highest priority and hence
       // will overwrite any previously set value.
-      if ((output.settings[j] == CONTENT_SETTING_DEFAULT) ||
+      if ((output.settings[j] == CONTENT_SETTING_DEFAULT &&
+           j != CONTENT_SETTINGS_TYPE_PLUGINS) ||
           IsDefaultContentSettingManaged(ContentSettingsType(j))) {
         output.settings[j] = GetDefaultContentSetting(ContentSettingsType(j));
       }
     }
   }
   return output;
 }
 
 ContentSettings HostContentSettingsMap::GetNonDefaultContentSettings(
     const GURL& url) const {
@@ skipping 664 matching lines @@
   }
 
   for (size_t i = 0; i < move_items.size(); ++i) {
     Value* pattern_settings_dictionary = NULL;
     all_settings_dictionary->RemoveWithoutPathExpansion(
         move_items[i].first, &pattern_settings_dictionary);
     all_settings_dictionary->SetWithoutPathExpansion(
         move_items[i].second, pattern_settings_dictionary);
   }
 }