Check HTMLMediaElement::supportsType() in MediaSource.isTypeSupported()

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 225 matching lines @@
     if (type.isNull() || type.isEmpty())
         return false;
 
     ContentType contentType(type);
     String codecs = contentType.parameter("codecs");
 
     // 2. If type does not contain a valid MIME type string, then return false.
     if (contentType.type().isEmpty())
         return false;
 
+    // Note: MediaSource.isTypeSupported() returning true implies that HTMLMediaElement.canPlayType() will return "maybe" or "probably"
+    // since it does not make sense for a MediaSource to support a type the HTMLMediaElement knows it cannot play.
+    if (HTMLMediaElement::supportsType(contentType, String()) == WebMimeRegistry::IsNotSupported)
+        return false;
+
     // 3. If type contains a media type or media subtype that the MediaSource does not support, then return false.
     // 4. If type contains at a codec that the MediaSource does not support, then return false.
     // 5. If the MediaSource does not support the specified combination of media type, media subtype, and codecs then return false.
     // 6. Return true.
     return MIMETypeRegistry::isSupportedMediaSourceMIMEType(contentType.type(), codecs);
 }
 
 const AtomicString& MediaSource::interfaceName() const
 {
     return EventTargetNames::MediaSource;
@@ skipping 303 matching lines @@
 
     m_asyncEventQueue->enqueueEvent(event.release());
 }
 
 URLRegistry& MediaSource::registry() const
 {
     return MediaSourceRegistry::registry();
 }
 
 } // namespace blink