FFmpegDemuxer: Clear |extra_data| when enabling bitstream conversion.

media/base/video_decoder_config.cc

Index: media/base/video_decoder_config.cc
diff --git a/media/base/video_decoder_config.cc b/media/base/video_decoder_config.cc
index 9bd7e555b4af27eda0a968e1e9461120b7158b96..731b11ee548637f025bea0ef59aa849cc6075514 100644
--- a/media/base/video_decoder_config.cc
+++ b/media/base/video_decoder_config.cc
@@ -68,6 +68,11 @@ VideoDecoderConfig::VideoDecoderConfig(const VideoDecoderConfig& other) =
 
 VideoDecoderConfig::~VideoDecoderConfig() {}
 
+void VideoDecoderConfig::set_extra_data(

[DaleCurtis, 2016/10/25 00:18:46]

Must be inlined to use hacker_style(). We have no other setters on this class,
so instead of making it mutable why not just construct a new one in the demuxer?

[sandersd (OOO until July 31), 2016/10/25 20:58:41]

Done.

+    const std::vector<uint8_t>& extra_data) {
+  extra_data_ = extra_data;
+}
+
 void VideoDecoderConfig::set_color_space_info(
     const gfx::ColorSpace& color_space_info) {
   color_space_info_ = color_space_info;