Add a flushing mechanism for the WebVTTParser

Source/core/loader/TextTrackLoader.cpp

Index: Source/core/loader/TextTrackLoader.cpp
diff --git a/Source/core/loader/TextTrackLoader.cpp b/Source/core/loader/TextTrackLoader.cpp
index 18528b854e1555efa5b8270db82f05bfdb7a491e..111395f2a62b25b4539b25577175580cbd51f1fc 100644
--- a/Source/core/loader/TextTrackLoader.cpp
+++ b/Source/core/loader/TextTrackLoader.cpp
@@ -109,6 +109,9 @@ void TextTrackLoader::notifyFinished(Resource* resource)
     if (m_state != Failed)
         m_state = resource->errorOccurred() ? Failed : Finished;
 
+    if (m_state == Finished && m_cueParser)
+        m_cueParser->flush();
+
     if (!m_cueLoadTimer.isActive())
         m_cueLoadTimer.startOneShot(0);