Convert the PluginService interface to be an async wrapper around PluginList.

content/browser/plugin_service.h

 // 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.
 
 // This class responds to requests from renderers for the list of plugins, and
 // also a proxy object for plugin instances.
 
 #ifndef CONTENT_BROWSER_PLUGIN_SERVICE_H_
 #define CONTENT_BROWSER_PLUGIN_SERVICE_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/singleton.h"
 #include "base/synchronization/waitable_event_watcher.h"
 #include "build/build_config.h"
 #include "content/browser/plugin_process_host.h"
 #include "content/browser/ppapi_plugin_process_host.h"
 #include "content/browser/ppapi_broker_process_host.h"
 #include "content/common/content_export.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
 #include "googleurl/src/gurl.h"
 #include "ipc/ipc_channel_handle.h"
-#include "webkit/plugins/webplugininfo.h"
 
 #if defined(OS_WIN)
 #include "base/memory/scoped_ptr.h"
 #include "base/win/registry.h"
 #endif
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 #include "base/files/file_path_watcher.h"
 #endif
 
 struct PepperPluginInfo;
 class PluginDirWatcherDelegate;
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace content {
 class ResourceContext;
 class PluginServiceFilter;
 }
 
+namespace webkit {
+namespace npapi {
+class PluginGroup;
+class PluginList;
+}
+}
+
 // This must be created on the main thread but it's only called on the IO/file
-// thread.
+// thread. This is an asynchronous wrapper around the PluginList interface for
+// querying plugin information, and this should instead of that class wherever
+// possible.
 class CONTENT_EXPORT PluginService
     : public base::WaitableEventWatcher::Delegate,
       public NotificationObserver {
  public:
   struct OverriddenPlugin {
     int render_process_id;
     int render_view_id;
     GURL url;  // If empty, the override applies to all urls in render_view.
     webkit::WebPluginInfo plugin;
   };
@@ skipping 49 matching lines @@
                      int render_view_id,
                      const content::ResourceContext& context,
                      const GURL& url,
                      const GURL& page_url,
                      const std::string& mime_type,
                      bool allow_wildcard,
                      bool* use_stale,
                      webkit::WebPluginInfo* info,
                      std::string* actual_mime_type);
 
-  // Returns a list of all plug-ins available to the resource context. Must be
-  // called on the FILE thread.
-  void GetPlugins(const content::ResourceContext& context,
-                  std::vector<webkit::WebPluginInfo>* plugins);
+  // Causes the plugin list to be reloaded if necessary. If |refresh| is true,
+  // a reload will be forced.
+  void LoadPluginList(bool refresh, const base::Closure& completion_callback);

[jam, 2011/09/21 23:45:13]

i think having only one GetPlugins function is better, with a boolean parameter.
no need to have two functions when one will do.

[jam, 2011/09/21 23:45:55]

please ignore this comment, i put before i wrote the other bigger reply

+
+  // Returns the list of cached plugin information. This can be called from any
+  // thread, but the data can be stale.

[Bernhard Bauer, 2011/09/21 22:47:05]

Nit: I think the more common case will be that the plug-in list has not yet been
loaded at all. Could you change the comment that way?

+  void GetPlugins(std::vector<webkit::WebPluginInfo>* plugins);
+
+  // Returns the list of cached plugin groups. This can be called from any
+  // thread, but note that the data can be stale.
+  void GetPluginGroups(std::vector<webkit::npapi::PluginGroup>* groups);
 
   // Tells all the renderer processes to throw away their cache of the plugin
   // list, and optionally also reload all the pages with plugins.
   // NOTE: can only be called on the UI thread.
   static void PurgePluginListCache(bool reload_pages);
 
   void set_filter(content::PluginServiceFilter* filter) {
     filter_ = filter;
   }
+  content::PluginServiceFilter* filter() { return filter_; }
 
  private:
   friend struct DefaultSingletonTraits<PluginService>;
 
   // Creates the PluginService object, but doesn't actually build the plugin
   // list yet.  It's generated lazily.
   PluginService();
   virtual ~PluginService();
 
   // base::WaitableEventWatcher::Delegate implementation.
   virtual void OnWaitableEventSignaled(base::WaitableEvent* waitable_event);
 
   // NotificationObserver implementation
   virtual void Observe(int type, const NotificationSource& source,
                        const NotificationDetails& details);
 
   void RegisterPepperPlugins();
 
   PepperPluginInfo* GetRegisteredPpapiPluginInfo(const FilePath& plugin_path);
 
+  // Function that is run on the FILE thread to load the plugins synchronously.
+  void GetPluginsInternal(base::MessageLoopProxy* target_loop,
+                          const base::Closure& completion_callback);
+
   // Helper so we can do the plugin lookup on the FILE thread.
   void GetAllowedPluginForOpenChannelToPlugin(
       int render_process_id,
       int render_view_id,
       const GURL& url,
       const GURL& page_url,
       const std::string& mime_type,
       PluginProcessHost::Client* client,
       const content::ResourceContext* resource_context);
 
@@ skipping 37 matching lines @@
   content::PluginServiceFilter* filter_;
 
   std::set<PluginProcessHost::Client*> pending_plugin_clients_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginService);
 };
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(PluginService);
 
 #endif  // CONTENT_BROWSER_PLUGIN_SERVICE_H_