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 ff3ac5b0079eaad191862c5bce60da8687bba712..41878989c7357e4e83a09d81dce2cff4de457be3 100644
--- a/content/renderer/media/websourcebuffer_impl.cc
+++ b/content/renderer/media/websourcebuffer_impl.cc
@@ -102,6 +102,11 @@ 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;
 }