Implement core of compliant MediaSource coded frame processing

content/renderer/media/websourcebuffer_impl.cc

Index: content/renderer/media/websourcebuffer_impl.cc
diff --git a/content/renderer/media/websourcebuffer_impl.cc b/content/renderer/media/websourcebuffer_impl.cc
index 93a996b6ece593937e15f1f744cffd886b865ca4..1b8e4fa143561c66d727cc304bb8bbe1d984bd68 100644
--- a/content/renderer/media/websourcebuffer_impl.cc
+++ b/content/renderer/media/websourcebuffer_impl.cc
@@ -108,6 +108,11 @@ bool WebSourceBufferImpl::setTimestampOffset(double offset) {
     return false;
 
   timestamp_offset_ = DoubleToTimeDelta(offset);
+
+  // http://www.w3.org/TR/media-source/#widl-SourceBuffer-timestampOffset
+  // Step 6: If the mode attribute equals "sequence", then set the group start
+  // timestamp to new timestamp offset.
+  demuxer_->SetGroupStartTimestampIfInSequenceMode(id_, timestamp_offset_);
   return true;
 }