Revert of Add groupid for media devices. Group audio devices.

media/audio/mock_audio_manager.cc

Index: media/audio/mock_audio_manager.cc
diff --git a/media/audio/mock_audio_manager.cc b/media/audio/mock_audio_manager.cc
index 5676b31151fdfa3f91690a17ff1c4dc69187f134..a3a6087849dccf3d11b7240c6ceff59d7c721f69 100644
--- a/media/audio/mock_audio_manager.cc
+++ b/media/audio/mock_audio_manager.cc
@@ -92,14 +92,6 @@
   return std::string();
 }
 
-std::string MockAudioManager::GetGroupIDOutput(const std::string& output_id) {
-  return "";
-}
-
-std::string MockAudioManager::GetGroupIDInput(const std::string& input_id) {
-  return "";
-}
-
 std::unique_ptr<AudioLog> MockAudioManager::CreateAudioLog(
     AudioLogFactory::AudioComponent component) {
   return nullptr;