Add Blink side support for SourceBuffer.appendWindowStart & SourceBuffer.appendWindowEnd.

Source/web/SourceBufferPrivateImpl.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 52 matching lines @@
 void SourceBufferPrivateImpl::remove(double start, double end)
 {
     m_sourceBuffer->remove(start, end);
 }
 
 bool SourceBufferPrivateImpl::setTimestampOffset(double offset)
 {
     return m_sourceBuffer->setTimestampOffset(offset);
 }
 
+void SourceBufferPrivateImpl::setAppendWindowStart(double start)
+{
+    if (!m_sourceBuffer)
+        return;
+    m_sourceBuffer->setAppendWindowStart(start);
+}
+
+void SourceBufferPrivateImpl::setAppendWindowEnd(double end)
+{
+    if (!m_sourceBuffer)
+        return;
+    m_sourceBuffer->setAppendWindowEnd(end);
+}
+
 void SourceBufferPrivateImpl::removedFromMediaSource()
 {
     m_sourceBuffer->removedFromMediaSource();
     m_sourceBuffer.clear();
 }
 
 }