Web MIDI: Improve device change monitornig on Windows

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"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/system_monitor/system_monitor.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
 
 namespace {
 
 class FakeMidiManager : public MidiManager {
  public:
   FakeMidiManager() : start_initialization_is_called_(false) {}
   ~FakeMidiManager() override {}
@@ skipping 213 matching lines @@
   EndSession(client.get(), 0, 0);
   client.reset();
 
   // Following function should not call the destructed |client| function.
   CompleteInitialization(MIDI_OK);
   base::RunLoop run_loop;
   run_loop.RunUntilIdle();
 }
 
 TEST_F(MidiManagerTest, CreateMidiManager) {
+  // SystemMonitor is needed on Windows.
+  base::SystemMonitor system_monitor;
+
   scoped_ptr<FakeMidiManagerClient> client;
   client.reset(new FakeMidiManagerClient);
 
   scoped_ptr<MidiManager> manager(MidiManager::Create());
   manager->StartSession(client.get());
 
   MidiResult result = client->WaitForResult();
   // This #ifdef needs to be identical to the one in media/midi/midi_manager.cc.
   // Do not change the condition for disabling this test.
 #if !defined(OS_MACOSX) && !defined(OS_WIN) && !defined(USE_ALSA) && \
     !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
   EXPECT_EQ(MIDI_NOT_SUPPORTED, result);
 #elif defined(USE_ALSA)
   // Temporary until http://crbug.com/371230 is resolved.
   EXPECT_TRUE((result == MIDI_OK) || (result == MIDI_INITIALIZATION_ERROR));
 #else
   EXPECT_EQ(MIDI_OK, result);
 #endif
 }
 
 }  // namespace
 
 }  // namespace media