Move some generic functions to AudioManagerBase to be inherited by platform-specific AudioManager***

media/audio/audio_input_volume_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 <cmath>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/win/scoped_com_initializer.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager_base.h"
@@ skipping 77 matching lines @@
   scoped_ptr<AudioManager> audio_manager_;
   ScopedCOMInitializer com_init_;
 };
 
 TEST_F(AudioInputVolumeTest, InputVolumeTest) {
   if (!CanRunAudioTests())
     return;
 
   AudioDeviceNames device_names;
   audio_manager_->GetAudioInputDeviceNames(&device_names);
-  DCHECK(!device_names.empty());
+  if (device_names.empty()) {
+    LOG(WARNING) << "Could not find any available input device";
+    return;
+  }
 
   for (AudioDeviceNames::const_iterator it = device_names.begin();
        it != device_names.end();
        ++it) {
     AudioInputStream* ais = CreateAndOpenStream(it->unique_id);
     if (!ais) {
       DLOG(WARNING) << "Failed to open stream for device " << it->unique_id;
       continue;
     }
 
@@ skipping 33 matching lines @@
     EXPECT_GT(current_volume, 0);
 
     // Restores the volume to the original value.
     ais->SetVolume(original_volume);
     current_volume = ais->GetVolume();
     EXPECT_EQ(original_volume, current_volume);
 
     ais->Close();
   }
 }