MSE: Complete letting SourceBuffer begin to do initialization segment received algorithm

Source/modules/mediasource/MediaSource.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 137 matching lines @@
     if (!webSourceBuffer) {
         ASSERT(exceptionState.code() == NotSupportedError || exceptionState.code() == QuotaExceededError);
         // 2. If type contains a MIME type that is not supported ..., then throw a NotSupportedError exception and abort these steps.
         // 3. If the user agent can't handle any more SourceBuffer objects then throw a QuotaExceededError exception and abort these steps
         return 0;
     }
 
     SourceBuffer* buffer = SourceBuffer::create(webSourceBuffer.release(), this, m_asyncEventQueue.get());
     // 6. Add the new object to sourceBuffers and fire a addsourcebuffer on that object.
     m_sourceBuffers->add(buffer);
-    // FIXME: Remove the following once Chromium calls WebSourceBufferClient::InitSegmentReceived()
-    setSourceBufferActive(buffer);
 
     // 7. Return the new object to the caller.
     return buffer;
 }
 
 void MediaSource::removeSourceBuffer(SourceBuffer* buffer, ExceptionState& exceptionState)
 {
     WTF_LOG(Media, "MediaSource::removeSourceBuffer() %p", this);
 
     // 2.2 https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#widl-MediaSource-removeSourceBuffer-void-SourceBuffer-sourceBuffer
@@ skipping 307 matching lines @@
     m_webMediaSource->markEndOfStream(eosStatus);
 }
 
 bool MediaSource::isOpen() const
 {
     return readyState() == openKeyword();
 }
 
 void MediaSource::setSourceBufferActive(SourceBuffer* sourceBuffer)
 {
-    if (m_activeSourceBuffers->contains(sourceBuffer))
-        return;
+    ASSERT(!m_activeSourceBuffers->contains(sourceBuffer));
 
     // https://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html#widl-MediaSource-activeSourceBuffers
     // SourceBuffer objects in SourceBuffer.activeSourceBuffers must appear in
     // the same order as they appear in SourceBuffer.sourceBuffers.
     // SourceBuffer transitions to active are not guaranteed to occur in the
     // same order as buffers in |m_sourceBuffers|, so this method needs to
     // insert |sourceBuffer| into |m_activeSourceBuffers|.
     size_t indexInSourceBuffers = m_sourceBuffers->find(sourceBuffer);
     ASSERT(indexInSourceBuffers != kNotFound);
 
@@ skipping 89 matching lines @@
 
     m_asyncEventQueue->enqueueEvent(event.release());
 }
 
 URLRegistry& MediaSource::registry() const
 {
     return MediaSourceRegistry::registry();
 }
 
 } // namespace blink