clang/win: Fix build after https://codereview.chromium.org/1248543002/

media/audio/win/audio_device_listener_win_unittest.cc

 // Copyright (c) 2012 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 <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "base/win/scoped_com_initializer.h"
 #include "media/audio/audio_manager.h"
 #include "media/audio/audio_unittest_util.h"
 #include "media/audio/win/audio_device_listener_win.h"
 #include "media/audio/win/core_audio_util_win.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using base::win::ScopedCOMInitializer;
 
 namespace media {
 
-static const char kNoDevice[] = "";
 static const char kFirstTestDevice[] = "test_device_0";
 static const char kSecondTestDevice[] = "test_device_1";
 
 class AudioDeviceListenerWinTest : public testing::Test {
  public:
   AudioDeviceListenerWinTest() {
     DCHECK(com_init_.succeeded());
   }
 
   virtual void SetUp() {
@@ skipping 66 matching lines @@
   EXPECT_CALL(*this, OnDeviceChange()).Times(1);
   ASSERT_TRUE(SimulateDefaultOutputDeviceChange(kFirstTestDevice));
 
   testing::Mock::VerifyAndClear(this);
   AdvanceLastDeviceChangeTime();
   EXPECT_CALL(*this, OnDeviceChange()).Times(1);
   ASSERT_TRUE(SimulateNullDefaultOutputDeviceChange());
 }
 
 }  // namespace media