Web MIDI: add blink APIs to notify device connection events

public/platform/WebMIDIAccessorClient.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 19 matching lines @@
 
 #ifndef WebMIDIAccessorClient_h
 #define WebMIDIAccessorClient_h
 
 #include "WebString.h"
 
 namespace blink {
 
 class WebMIDIAccessorClient {
 public:
+    // FIXME: Remove deprecated interfaces that do not have |active| argument.
     virtual void didAddInputPort(const WebString& id, const WebString& manufacturer, const WebString& name, const WebString& version) = 0;
     virtual void didAddOutputPort(const WebString& id, const WebString& manufacturer, const WebString& name, const WebString& version) = 0;
 
+    virtual void didAddInputPort(const WebString& id, const WebString& manufacturer, const WebString& name, const WebString& version, bool active) = 0;
+    virtual void didAddOutputPort(const WebString& id, const WebString& manufacturer, const WebString& name, const WebString& version, bool active) = 0;
+    virtual void didSetInputPortState(unsigned portIndex, bool active) = 0;
+    virtual void didSetOutputPortState(unsigned portIndex, bool active) = 0;
+
     virtual void didStartSession(bool success, const WebString& error, const WebString& message) = 0;
 
     // |timeStamp| is in milliseconds according to the Web MIDI API.
     virtual void didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp) = 0;
 
 protected:
     virtual ~WebMIDIAccessorClient() { }
 };
 
 } // namespace blink
 
 #endif // WebMIDIAccessorClient_h