Web MIDI: introduce MidiManager::Shutdown to shutdown gracefully

content/browser/media/midi_host_unittest.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 "content/browser/media/midi_host.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
 #include "content/common/media/midi_messages.h"
@@ skipping 86 matching lines @@
   void ShutdownForBadMessage() override {}
 };
 
 class MidiHostTest : public testing::Test {
  public:
   MidiHostTest()
       : io_browser_thread_(BrowserThread::IO, &message_loop_),
         host_(new MidiHostForTesting(kRenderProcessId, &manager_)),
         data_(kNoteOn, kNoteOn + arraysize(kNoteOn)),
         port_id_(0) {}
+  ~MidiHostTest() override {
+    manager_.Shutdown();
+    RunLoopUntilIdle();
+  }
 
  protected:
   void AddOutputPort() {
     const std::string id = base::StringPrintf("i-can-%d", port_id_++);
     const std::string manufacturer("yukatan");
     const std::string name("doki-doki-pi-pine");
     const std::string version("3.14159265359");
     media::midi::MidiPortState state = media::midi::MIDI_PORT_CONNECTED;
     media::midi::MidiPortInfo info(id, manufacturer, name, version, state);
 
@@ skipping 107 matching lines @@
   // Sending data to port 0 and 1 should be delivered now.
   OnSendData(port0);
   OnSendData(port1);
   RunLoopUntilIdle();
   EXPECT_EQ(3U, GetEventSize());
   CheckSendEventAt(1, port0);
   CheckSendEventAt(2, port1);
 }
 
 }  // namespace conent