Implement disabling and enabling media tracks

media/filters/chunk_demuxer.cc

Index: media/filters/chunk_demuxer.cc
diff --git a/media/filters/chunk_demuxer.cc b/media/filters/chunk_demuxer.cc
index 5e9f6795fa2ac81b00dce13d2b66c3d8cfc0408e..4480b27ad460704e171538519bd6b971fbc79765 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -15,6 +15,7 @@
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/base/media_tracks.h"
@@ -241,6 +242,14 @@ void ChunkDemuxerStream::Read(const ReadCB& read_cb) {
   DCHECK(read_cb_.is_null());
 
   read_cb_ = BindToCurrentLoop(read_cb);
+
+  if (!is_enabled_) {
+    DVLOG(1) << "Read from disabled stream, returning EOS";
+    base::ResetAndReturn(&read_cb_).Run(kOk,
+                                        StreamParserBuffer::CreateEOSBuffer());
+    return;
+  }
+
   CompletePendingReadIfPossible_Locked();
 }
 
@@ -269,6 +278,28 @@ VideoRotation ChunkDemuxerStream::video_rotation() {
   return VIDEO_ROTATION_0;
 }
 
+bool ChunkDemuxerStream::enabled() const {
+  base::AutoLock auto_lock(lock_);
+  return is_enabled_;
+}
+
+void ChunkDemuxerStream::set_enabled(bool enabled, base::TimeDelta timestamp) {
+  base::AutoLock auto_lock(lock_);
+
+  if (enabled == is_enabled_)
+    return;
+
+  is_enabled_ = enabled;
+  if (enabled) {
+    DCHECK(stream_);
+    stream_->Seek(timestamp);
+  } else if (!read_cb_.is_null()) {
+    DVLOG(1) << "Read from disabled stream, returning EOS";
+    base::ResetAndReturn(&read_cb_).Run(kOk,
+                                        StreamParserBuffer::CreateEOSBuffer());
+  }
+}
+
 TextTrackConfig ChunkDemuxerStream::text_track_config() {
   CHECK_EQ(type_, TEXT);
   base::AutoLock auto_lock(lock_);