Web MIDI: do not keep virtual synth open

media/midi/midi_manager_win.cc

 // Copyright 2013 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_win.h"
 
 #include <windows.h>
 #include <ks.h>
 #include <ksmedia.h>
 #include <mmreg.h>
@@ skipping 71 matching lines @@
                 << " midiOutGetErrorText error: " << get_result;
     return std::string();
   }
   return base::WideToUTF8(text);
 }
 
 std::string MmversionToString(MMVERSION version) {
   return base::StringPrintf("%d.%d", HIBYTE(version), LOBYTE(version));
 }
 
+void CloseOutputPortOnTaskThread(HMIDIOUT midi_out_handle) {
+  midiOutClose(midi_out_handle);
+}
+
 class MIDIHDRDeleter {
  public:
   void operator()(MIDIHDR* header) {
     if (!header)
       return;
     delete[] static_cast<char*>(header->lpData);
     header->lpData = NULL;
     header->dwBufferLength = 0;
     delete header;
   }
@@ skipping 719 matching lines @@
     result = midiOutGetDevCaps(
         device_id, reinterpret_cast<LPMIDIOUTCAPSW>(&caps), sizeof(caps));
     if (result != MMSYSERR_NOERROR) {
       DLOG(ERROR) << "midiInGetDevCaps failed: " << GetOutErrorMessage(result);
       return;
     }
     auto state =
         make_scoped_refptr(new MidiOutputDeviceState(MidiDeviceInfo(caps)));
     state->midi_handle = midi_out_handle;
     const auto& state_device_info = state->device_info;
-    if (IsUnsupportedDevice(state_device_info))
+    if (IsUnsupportedDevice(state_device_info)) {
+      task_thread_.task_runner()->PostTask(
+          FROM_HERE, base::Bind(&CloseOutputPortOnTaskThread, midi_out_handle));
       return;
+    }
     bool add_new_port = false;
     uint32_t port_number = 0;
     {
       base::AutoLock auto_lock(output_ports_lock_);
       const auto it = unused_output_ports_.find(state_device_info);
       if (it == unused_output_ports_.end()) {
         port_number = static_cast<uint32_t>(output_ports_.size());
         add_new_port = true;
         output_ports_.push_back(nullptr);
         output_ports_ages_.push_back(0);
@@ skipping 351 matching lines @@
 }
 
 MidiManager* MidiManager::Create() {
   if (base::FeatureList::IsEnabled(features::kMidiManagerWinrt) &&
       base::win::GetVersion() >= base::win::VERSION_WIN10)
     return new MidiManagerWinrt();
   return new MidiManagerWin();
 }
 
 }  // namespace midi