[Web MIDI] Use Android MIDI API.

media/midi/midi_manager_usb.cc

 // Copyright 2014 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 "media/midi/midi_manager_usb.h"
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "media/midi/midi_scheduler.h"
@@ skipping 119 matching lines @@
 
   std::string manufacturer(device->GetManufacturer());
   std::string product_name(device->GetProductName());
   std::string version(device->GetDeviceVersion());
 
   for (size_t j = 0; j < jacks.size(); ++j) {
     // Port ID must be unique in a MIDI manager. This ID setting is
     // sufficiently unique although there is no user-friendly meaning.
     // TODO(yhirano): Use a hashed string as ID.
     std::string id(
-        base::StringPrintf("port-%d-%ld", device_id, static_cast<long>(j)));
+        base::StringPrintf("usb:port-%d-%ld", device_id, static_cast<long>(j)));
     if (jacks[j].direction() == UsbMidiJack::DIRECTION_OUT) {
       output_streams_.push_back(new UsbMidiOutputStream(jacks[j]));
       AddOutputPort(MidiPortInfo(id, manufacturer, product_name, version,
                                  MIDI_PORT_OPENED));
     } else {
       DCHECK_EQ(jacks[j].direction(), UsbMidiJack::DIRECTION_IN);
       input_stream_->Add(jacks[j]);
       AddInputPort(MidiPortInfo(id, manufacturer, product_name, version,
                                 MIDI_PORT_OPENED));
     }
   }
   return true;
 }
 
 }  // namespace midi
 }  // namespace media