Oilpan: have the media element safely close its MediaSource.

Source/modules/mediasource/SourceBuffer.cpp

Index: Source/modules/mediasource/SourceBuffer.cpp
diff --git a/Source/modules/mediasource/SourceBuffer.cpp b/Source/modules/mediasource/SourceBuffer.cpp
index 741e25c67df41187718a190c119e5af95408a4ec..f0d2e7839d653734e7adfeb041bafe3661ce8723 100644
--- a/Source/modules/mediasource/SourceBuffer.cpp
+++ b/Source/modules/mediasource/SourceBuffer.cpp
@@ -105,7 +105,11 @@ SourceBuffer::SourceBuffer(PassOwnPtr<WebSourceBuffer> webSourceBuffer, MediaSou
 
 SourceBuffer::~SourceBuffer()
 {
+#if ENABLE(OILPAN)
+    removedFromMediaSource();

[haraken, 2014/07/03 03:25:37]

Just help me understand: What is this change for?

[sof, 2014/07/03 06:22:24]

If MediaSource and HTMLMediaElement die at the same time, then MediaSource will
not be explicitly closed. This takes care of the lack of such wrt reset'ing the
MediaSource's SourceBuffers.

[haraken, 2014/07/03 06:40:31]

Hmm, in my understanding, SourceBuffers are owned by the MediaSource, so the
SourceBuffers always die with the MediaSource. Then we don't need to call
removedFromMediaSource() in ~SourceBuffer().

[sof, 2014/07/03 06:52:25]

That matches my understanding of ownership (via SourceBufferList.) But close()
(via onReadyStateChange()) will explicitly call removeFromMediaSource() on them,
so if it doesn't, someone else will.

Hmm, looking at all that SourceBuffer::abortIfUpdating() will potentially do,
that's too much - no need to fire events, for instance. Will address that.

+#else
     ASSERT(isRemoved());
+#endif
     ASSERT(!m_loader);
     ASSERT(!m_stream);
 }