Clears the media keys from the given element. This is only allowed if the element's src isn't set. https://bugs.chromium.org/p/chromium/issues/detail?id=462365#c7
Creates the key session.
The initialization data from the 'encrypted' event.
Sets the media keys on the given element.
Sets the server certificate on the media keys.
A Promise that resolves to a boolean. If the Key System implementation represented by this object's content decryption module's implementation value does not support server certificates, return a promise resolved with false.
The server certificate data.
CommonMediaKeys for unprefixed EME implementations.