Move key frame flag from StreamParserBuffer to DecoderBuffer

media/base/fake_text_track_stream.cc

Index: media/base/fake_text_track_stream.cc
diff --git a/media/base/fake_text_track_stream.cc b/media/base/fake_text_track_stream.cc
index f18e5403b4e3c2ebbf19ea1f2078657f6b8935f8..33749682e81d4ea671a30cc37c492693671ba3cd 100644
--- a/media/base/fake_text_track_stream.cc
+++ b/media/base/fake_text_track_stream.cc
@@ -67,6 +67,9 @@ void FakeTextTrackStream::SatisfyPendingRead(
   buffer->set_timestamp(start);
   buffer->set_duration(duration);
 
+  // Assume all fake text buffers are keyframes.
+  buffer->set_is_key_frame(true);
+
   base::ResetAndReturn(&read_cb_).Run(kOk, buffer);
 }