Add SupportsConfigChanges() to DemuxerStream.

media/filters/fake_demuxer_stream.cc

Index: media/filters/fake_demuxer_stream.cc
diff --git a/media/filters/fake_demuxer_stream.cc b/media/filters/fake_demuxer_stream.cc
index 51e4236b7df6d4ff3f884b27ffa92a1f28021861..23c49d2a9283b195f2c58e767fd17fbc64e6feba 100644
--- a/media/filters/fake_demuxer_stream.cc
+++ b/media/filters/fake_demuxer_stream.cc
@@ -85,6 +85,10 @@ void FakeDemuxerStream::EnableBitstreamConverter() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 }
 
+bool FakeDemuxerStream::SupportsConfigChanges() {
+  return true;

[scherkus (not reviewing), 2014/03/25 22:16:47]

is this needed for some tests?

do we need some tests to cover the false behaviour?

[rileya (GONE FROM CHROMIUM), 2014/03/25 22:43:19]

Yeah, it's used by the tests. I made it return true or false depending on
whether the FDS was initialized with multiple configs. I also added a test for
the 'false' behavior.

+}
+
 void FakeDemuxerStream::HoldNextRead() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   read_to_hold_ = next_read_num_;