media: Always define |cdm_id| in CdmContext.

media/cdm/aes_decryptor.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_CRYPTO_AES_DECRYPTOR_H_
 #define MEDIA_CRYPTO_AES_DECRYPTOR_H_
 
 #include <set>
 #include <string>
 
@@ skipping 42 matching lines @@
                      int response_length,
                      scoped_ptr<SimpleCdmPromise> promise) override;
   void CloseSession(const std::string& session_id,
                     scoped_ptr<SimpleCdmPromise> promise) override;
   void RemoveSession(const std::string& session_id,
                      scoped_ptr<SimpleCdmPromise> promise) override;
   CdmContext* GetCdmContext() override;
 
   // CdmContext implementation.
   Decryptor* GetDecryptor() override;
-#if defined(ENABLE_BROWSER_CDMS)
   int GetCdmId() const override;
-#endif  // defined(ENABLE_BROWSER_CDMS)
 
   // Decryptor implementation.
   void RegisterNewKeyCB(StreamType stream_type,
                         const NewKeyCB& key_added_cb) override;
   void Decrypt(StreamType stream_type,
                const scoped_refptr<DecoderBuffer>& encrypted,
                const DecryptCB& decrypt_cb) override;
   void CancelDecrypt(StreamType stream_type) override;
   void InitializeAudioDecoder(const AudioDecoderConfig& config,
                               const DecoderInitCB& init_cb) override;
@@ skipping 80 matching lines @@
   // Protect |new_audio_key_cb_| and |new_video_key_cb_| as they are set on the
   // main thread but called on the media thread.
   mutable base::Lock new_key_cb_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(AesDecryptor);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CRYPTO_AES_DECRYPTOR_H_