Allow to use {FFmpeg/Vpx}VideoDecoder from a UtilityProcess

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 c9b3b3060b4096c7b59b4da11e499c35e9fb0ee4..ccb4f697849b0563a9dabcb8584e2daa3bd8575a 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -24,6 +24,7 @@
 #include "media/base/media_switches.h"
 #include "media/base/timestamp_constants.h"
 #include "media/base/video_frame.h"
+#include "media/base/video_frame_provider.h"
 #include "media/base/video_util.h"
 #include "media/ffmpeg/ffmpeg_common.h"
 #include "media/filters/ffmpeg_glue.h"
@@ -116,6 +117,14 @@ FFmpegVideoDecoder::FFmpegVideoDecoder()
   thread_checker_.DetachFromThread();
 }
 
+FFmpegVideoDecoder::FFmpegVideoDecoder(
+    std::unique_ptr<VideoFrameProvider> video_frame_provider)
+    : state_(kUninitialized),
+      frame_pool_(std::move(video_frame_provider)),
+      decode_nalus_(false) {
+  thread_checker_.DetachFromThread();
+}
+
 int FFmpegVideoDecoder::GetVideoBuffer(struct AVCodecContext* codec_context,
                                        AVFrame* frame,
                                        int flags) {