Web MIDI: introduce MidiManager::Shutdown to shutdown gracefully

media/midi/midi_manager.h

Index: media/midi/midi_manager.h
diff --git a/media/midi/midi_manager.h b/media/midi/midi_manager.h
index 957c84d427f0dc85b291cd6b9cee188067dca5d7..8f51f133aa9e3fe3e879cff8a1e26c6a47049164 100644
--- a/media/midi/midi_manager.h
+++ b/media/midi/midi_manager.h
@@ -75,6 +75,10 @@ class MIDI_EXPORT MidiManager {
   // thread.
   static MidiManager* Create();
 
+  // Called on the CrBrowserMain thread to notify the Chrome_IOThread will stop
+  // and the instance will be destructed on the CrBrowserMain thread soon.
+  void Shutdown();
+
   // A client calls StartSession() to receive and send MIDI data.
   // If the session is ready to start, the MIDI system is lazily initialized
   // and the client is registered to receive MIDI data.
@@ -119,6 +123,12 @@ class MIDI_EXPORT MidiManager {
   // |result| should be Result::OK on success, otherwise a proper Result.
   virtual void StartInitialization();
 
+  // Finalizes the platform dependent MIDI system. Called on Chrome_IOThread
+  // thread and the thread will stop immediately after this call.
+  // Platform dependent resources that were allocated on the Chrome_IOThread
+  // should be disposed inside this method.
+  virtual void Finalize() {}
+
   // Called from a platform dependent implementation of StartInitialization().
   // It invokes CompleteInitializationInternal() on the thread that calls
   // StartSession() and distributes |result| to MIDIManagerClient objects in
@@ -169,6 +179,9 @@ class MIDI_EXPORT MidiManager {
   // Keeps true if platform dependent initialization is already completed.
   bool initialized_;
 
+  // Keeps false until Shutdown() is called.
+  bool shutted_down_;

[yhirano, 2015/09/07 06:00:25]

"shut"'s past participle form is "shut", not "shutted".

[Takashi Toyoshima, 2015/09/07 19:04:39]

Done.

+
   // Keeps the platform dependent initialization result if initialization is
   // completed. Otherwise keeps Result::NOT_INITIALIZED.
   Result result_;