Add an IPC to return the platform supported key-system names in Android.

components/cdm/renderer/widevine_key_systems.h

 // Copyright 2014 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 COMPONENTS_CDM_RENDERER_WIDEVINE_KEY_SYSTEMS_H_
 #define COMPONENTS_CDM_RENDERER_WIDEVINE_KEY_SYSTEMS_H_
 
 #include <vector>
 
 #include "content/public/renderer/key_system_info.h"
 
 namespace cdm {
 
 enum WidevineCdmType {
   WIDEVINE,
 #if defined(OS_ANDROID)
   WIDEVINE_HR_NON_COMPOSITING,
 #endif  // defined(OS_ANDROID)
 };
 
 void AddWidevineWithCodecs(
     WidevineCdmType widevine_cdm_type,
     content::SupportedCodecs supported_codecs,
     std::vector<content::KeySystemInfo>* concrete_key_systems);
 
-#if defined(OS_ANDROID)
-void AddAndroidWidevine(
-    std::vector<content::KeySystemInfo>* concrete_key_systems);
-#endif  // defined(OS_ANDROID)
-
 }  // namespace cdm
 
 #endif  // COMPONENTS_CDM_RENDERER_WIDEVINE_KEY_SYSTEMS_H_