media: Remove SetCdmReadyCB and CdmReadyCB (part 1).

media/filters/ffmpeg_video_decoder.cc

Index: media/filters/ffmpeg_video_decoder.cc
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index 38d4405ee3843620672104fa3bc85301bf39e9ae..872bf60010c7901f608744a9875aca41c3bc6091 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -168,7 +168,7 @@ std::string FFmpegVideoDecoder::GetDisplayName() const {
 
 void FFmpegVideoDecoder::Initialize(const VideoDecoderConfig& config,
                                     bool low_delay,
-                                    const SetCdmReadyCB& /* set_cdm_ready_cb */,
+                                    CdmContext* /* cdm_context */,
                                     const InitCB& init_cb,
                                     const OutputCB& output_cb) {
   DCHECK(thread_checker_.CalledOnValidThread());