Keep NaCl plugins used in app background pages alive when active.

ppapi/proxy/plugin_globals.h

 // 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.
 
 #ifndef PPAPI_PROXY_PLUGIN_GLOBALS_H_
 #define PPAPI_PROXY_PLUGIN_GLOBALS_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 56 matching lines @@
   virtual void LogWithSource(PP_Instance instance,
                              PP_LogLevel level,
                              const std::string& source,
                              const std::string& value) OVERRIDE;
   virtual void BroadcastLogWithSource(PP_Module module,
                                       PP_LogLevel level,
                                       const std::string& source,
                                       const std::string& value) OVERRIDE;
   virtual MessageLoopShared* GetCurrentMessageLoop() OVERRIDE;
   base::TaskRunner* GetFileTaskRunner() OVERRIDE;
+  virtual void MarkPluginIsActive() OVERRIDE;
 
   // Returns the channel for sending to the browser.
   IPC::Sender* GetBrowserSender();
 
   // Returns the language code of the current UI language.
   std::string GetUILanguage();
 
   // Sets the active url which is reported by breakpad.
   void SetActiveURL(const std::string& url);
 
@@ skipping 39 matching lines @@
   // is known. This will be used for error logging.
   void set_plugin_name(const std::string& name) { plugin_name_ = name; }
 
   // The embedder should call this function when the command line is known.
   void set_command_line(const std::string& c) { command_line_ = c; }
 
   ResourceReplyThreadRegistrar* resource_reply_thread_registrar() {
     return resource_reply_thread_registrar_.get();
   }
 
+  // Interval to limit how many IPC messages are sent indicating that the plugin
+  // is active and should be kept alive. The value must be smaller than any
+  // threshold used to kill inactive plugins by the embedder host.
+  int keepalive_throttle_interval_milliseconds() const;
+  void set_keepalive_throttle_interval_milliseconds(int i);
+
  private:
   class BrowserSender;
 
   // PpapiGlobals overrides.
   virtual bool IsPluginGlobals() const OVERRIDE;
 
+  // Locks the proxy lock and releases the throttle on keepalive IPC messages.
+  void OnReleaseKeepaliveThrottle();
+
   static PluginGlobals* plugin_globals_;
 
   PluginProxyDelegate* plugin_proxy_delegate_;
   PluginResourceTracker plugin_resource_tracker_;
   PluginVarTracker plugin_var_tracker_;
   scoped_refptr<CallbackTracker> callback_tracker_;
 
   scoped_ptr<base::ThreadLocalStorage::Slot> msg_loop_slot_;
   // Note that loop_for_main_thread's constructor sets msg_loop_slot_, so it
   // must be initialized after msg_loop_slot_ (hence the order here).
   scoped_refptr<MessageLoopResource> loop_for_main_thread_;
 
   // Name of the plugin used for error logging. This will be empty until
   // set_plugin_name is called.
   std::string plugin_name_;
 
   // Command line for the plugin. This will be empty until set_command_line is
   // called.
   std::string command_line_;
 
   scoped_ptr<BrowserSender> browser_sender_;
 
   // Thread for performing potentially blocking file operations. It's created
   // lazily, since it might not be needed.
   scoped_ptr<base::Thread> file_thread_;
 
   scoped_refptr<ResourceReplyThreadRegistrar> resource_reply_thread_registrar_;
 
+  // Indicates activity by the plugin. Used to monitor when a plugin can be
+  // shutdown due to idleness. Current needs do not require differentiating
+  // between idle state between multiple instances, if any are active they are
+  // all considered active.
+  bool plugin_recently_active_;
+
+  int keepalive_throttle_interval_milliseconds_;
+
+  // Member variables should appear before the WeakPtrFactory, see weak_ptr.h.
+  base::WeakPtrFactory<PluginGlobals> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PluginGlobals);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif   // PPAPI_PROXY_PLUGIN_GLOBALS_H_