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..2ea7c2dc3e1722d06657bf8e4dea2c336c4ebdb3 100644
--- a/Source/modules/mediasource/WebKitSourceBuffer.cpp
+++ b/Source/modules/mediasource/WebKitSourceBuffer.cpp
@@ -136,7 +136,11 @@ 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());
+
+    // |dummyNewTimestampOffset| is ignored because the prefixed API does not allow appends to update

[jamesr, 2014/02/27 01:49:56]

if the parameter is only optionally needed by callers, then a cleaner way to
express it is to pass NULL in for callers that don't care and have the
implementation only update the value if it is non-NULL

[wolenetz, 2014/02/27 03:29:58]

Done.

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