Add a preference to clear plugin data on browser shutdown.

chrome/browser/plugin_service.cc

 // Copyright (c) 2010 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 "build/build_config.h"
 
 #include "chrome/browser/plugin_service.h"
 
 #include "base/command_line.h"
 #include "base/path_service.h"
@@ skipping 202 matching lines @@
     const FilePath& plugin_path) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   PluginProcessHost* plugin_host = FindPluginProcess(plugin_path);
   if (plugin_host)
     return plugin_host;
 
   WebPluginInfo info;
   if (!NPAPI::PluginList::Singleton()->GetPluginInfoByPath(
       plugin_path, &info)) {
-    NOTREACHED();
     return NULL;
   }
 
   // This plugin isn't loaded by any plugin process, so create a new process.
   scoped_ptr<PluginProcessHost> new_host(new PluginProcessHost());
   if (!new_host->Init(info, ui_locale_)) {
     NOTREACHED();  // Init is not expected to fail
     return NULL;
   }
 
@@ skipping 190 matching lines @@
     info.mime_types = ASCIIToWide(JoinString(plugins[i].mime_types, '|'));
 
     // These NPAPI entry points will never be called.  TODO(darin): Come up
     // with a cleaner way to register pepper plugins with the NPAPI PluginList,
     // or perhaps refactor the PluginList to be less specific to NPAPI.
     memset(&info.entry_points, 0, sizeof(info.entry_points));
 
     NPAPI::PluginList::Singleton()->RegisterInternalPlugin(info);
   }
 }