Enable round-tripping and updating of SourceBuffer timestamp offset

Source/modules/mediasource/WebKitSourceBuffer.cpp

Index: Source/modules/mediasource/WebKitSourceBuffer.cpp
diff --git a/Source/modules/mediasource/WebKitSourceBuffer.cpp b/Source/modules/mediasource/WebKitSourceBuffer.cpp
index f460311fb3dc0bea48d95d62227b62850ebe8afb..1332e277eebb5d20b4fd1a0abb843e33b97d210d 100644
--- a/Source/modules/mediasource/WebKitSourceBuffer.cpp
+++ b/Source/modules/mediasource/WebKitSourceBuffer.cpp
@@ -136,7 +136,10 @@ void WebKitSourceBuffer::append(PassRefPtr<Uint8Array> data, ExceptionState& exc
     m_source->openIfInEndedState();
 
     // Steps 6 & beyond are handled by m_webSourceBuffer.
-    m_webSourceBuffer->append(data->data(), data->length());
+
+    // Only "sequence" mode coded frame processing, not in prefixed API, may update timestamp offset.

[acolwell GONE FROM CHROMIUM, 2014/02/27 01:24:45]

nit: This comment is a little confusing. How about something line
"|dummyNewTimestampOffset| is ignored because the prefixed API does not allow
timestampOffset updates."?

[wolenetz, 2014/02/27 01:44:56]

Done.

+    double dummyNewTimestampOffset;
+    m_webSourceBuffer->append(data->data(), data->length(), &dummyNewTimestampOffset);
 }
 
 void WebKitSourceBuffer::abort(ExceptionState& exceptionState)