Enable round-tripping and updating of WebSourceBufferImpl timestamp offset

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 a7d8d8a537803b4f9a2a8bdf42777af21720a5a0..686307640f099ad5f49db0531ea51129f043e124 100644
--- a/content/renderer/media/websourcebuffer_impl.cc
+++ b/content/renderer/media/websourcebuffer_impl.cc
@@ -60,7 +60,14 @@ blink::WebTimeRanges WebSourceBufferImpl::buffered() {
 }
 
 void WebSourceBufferImpl::append(const unsigned char* data, unsigned length) {
-  demuxer_->AppendData(id_, data, length);
+  append(data, length, NULL);
+}
+
+void WebSourceBufferImpl::append(
+    const unsigned char* data,
+    unsigned length,
+    double* timestamp_offset) {
+  demuxer_->AppendData(id_, data, length, timestamp_offset);
 }
 
 void WebSourceBufferImpl::abort() {