Revert of MediaPerceptionPrivate API impl and testing.

extensions/browser/api/media_perception_private/conversion_utils.h

-// Copyright 2017 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.
-
-#ifndef EXTENSIONS_BROWSER_API_MEDIA_PERCEPTION_PRIVATE_CONVERSION_UTILS_H_
-#define EXTENSIONS_BROWSER_API_MEDIA_PERCEPTION_PRIVATE_CONVERSION_UTILS_H_
-
-#include "chromeos/media_perception/media_perception.pb.h"
-#include "extensions/common/api/media_perception_private.h"
-
-namespace extensions {
-namespace api {
-namespace media_perception_private {
-
-// Converts State proto messages to State objects (generated by the
-// media_perception_private.idl).
-State StateProtoToIdl(const mri::State& state);
-
-// Converts State objects (generated by the media_perception_private.idl) to
-// State proto messages.
-mri::State StateIdlToProto(const State& state);
-
-// Converts MediaPerception proto messages to MediaPerception objects
-// (generated by the media_perception_private.idl).
-MediaPerception MediaPerceptionProtoToIdl(
-    const mri::MediaPerception& media_perception);
-
-// Converts Diagnostics proto messages to Diagnostics objects (generated by the
-// media_perception_private.idl).
-Diagnostics DiagnosticsProtoToIdl(const mri::Diagnostics& diagnostics);
-
-}  //  namespace media_perception_private
-}  //  namespace api
-}  //  namespace extensions
-
-#endif  // EXTENSIONS_BROWSER_API_MEDIA_PERCEPTION_PRIVATE_CONVERSION_UTILS_H_