EME: Remove the concept of a parent key system.

media/base/key_system_info.h

 // Copyright 2013 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 MEDIA_BASE_KEY_SYSTEM_INFO_H_
 #define MEDIA_BASE_KEY_SYSTEM_INFO_H_
 
 #include <string>
 
 #include "build/build_config.h"
 #include "media/base/eme_constants.h"
 #include "media/base/media_export.h"
 
 // Definitions:
 // * Key system
 //    https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#key-system
 // * Concrete key system
 //    A key system string that can be instantiated, such as
 //    via the MediaKeys constructor. Examples include "org.w3.clearkey" and
 //    "com.widevine.alpha".
 // * Abstract key system
 //    A key system string that cannot be instantiated like a concrete key system
 //    but is otherwise useful, such as in discovery using isTypeSupported().
-// TODO(ddorwin): Remove the concept of a parent key system now that prefixed
-// has been removed. https://crbug.com/249976
-// * Parent key system
-//    A key system string that is one level up from the child key system. It may
-//    be an abstract key system.
-//    As an example, "com.example" is the parent of "com.example.foo".
 
 namespace media {
 
 // Contains information about an EME key system as well as how to instantiate
 // the corresponding CDM.
 struct MEDIA_EXPORT KeySystemInfo {
   KeySystemInfo();
   ~KeySystemInfo();
 
   std::string key_system;
 
   InitDataTypeMask supported_init_data_types = kInitDataTypeMaskNone;
   SupportedCodecs supported_codecs = EME_CODEC_NONE;
 #if defined(OS_ANDROID)
   SupportedCodecs supported_secure_codecs = EME_CODEC_NONE;
 #endif  // defined(OS_ANDROID)
   EmeRobustness max_audio_robustness = EmeRobustness::INVALID;
   EmeRobustness max_video_robustness = EmeRobustness::INVALID;
   EmeSessionTypeSupport persistent_license_support =
       EmeSessionTypeSupport::INVALID;
   EmeSessionTypeSupport persistent_release_message_support =
       EmeSessionTypeSupport::INVALID;
   EmeFeatureSupport persistent_state_support = EmeFeatureSupport::INVALID;
   EmeFeatureSupport distinctive_identifier_support = EmeFeatureSupport::INVALID;
 
-  // A hierarchical parent for |key_system|. This value can be used to check
-  // supported types but cannot be used to instantiate a MediaKeys object.
-  // Only one parent key system is currently supported per concrete key system.
-  std::string parent_key_system;
-
   // The following indicate how the corresponding CDM should be instantiated.
   bool use_aes_decryptor = false;
 #if defined(ENABLE_PEPPER_CDMS)
   std::string pepper_type;
 #endif
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_KEY_SYSTEM_INFO_H_