Web MIDI: introduce MidiManager::Shutdown to shutdown gracefully

media/midi/midi_manager_unittest.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.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 82 matching lines @@
   bool wait_for_result_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeMidiManagerClient);
 };
 
 class MidiManagerTest : public ::testing::Test {
  public:
   MidiManagerTest()
       : manager_(new FakeMidiManager),
         message_loop_(new base::MessageLoop) {}
-  ~MidiManagerTest() override {}
+  ~MidiManagerTest() override {
+    manager_->Shutdown();
+  }
 
  protected:
   void StartTheFirstSession(FakeMidiManagerClient* client) {
     EXPECT_FALSE(manager_->start_initialization_is_called_);
     EXPECT_EQ(0U, manager_->GetClientCount());
     EXPECT_EQ(0U, manager_->GetPendingClientCount());
     manager_->StartSession(client);
     EXPECT_EQ(0U, manager_->GetClientCount());
     EXPECT_EQ(1U, manager_->GetPendingClientCount());
     EXPECT_TRUE(manager_->start_initialization_is_called_);
@@ skipping 146 matching lines @@
   // Do not change the condition for disabling this test.
 #if !defined(OS_MACOSX) && !defined(OS_WIN) && \
     !(defined(USE_ALSA) && defined(USE_UDEV)) && !defined(OS_ANDROID)
   EXPECT_EQ(Result::NOT_SUPPORTED, result);
 #elif defined(USE_ALSA)
   // Temporary until http://crbug.com/371230 is resolved.
   EXPECT_TRUE(result == Result::OK || result == Result::INITIALIZATION_ERROR);
 #else
   EXPECT_EQ(Result::OK, result);
 #endif
+
+  manager->Shutdown();
 }
 
 }  // namespace
 
 }  // namespace midi
 }  // namespace media