This task comes from piman@ shareable image design doc (https://docs.google.com/document/d/12qYPeN819JkdNGbPcKBA0rfPXSOIE3aIaQVrAZ4I1lM).

Android specific code (https://cs.chromium.org/chromium/src/media/blink/webmediaplayer_cast_android.cc). It does create+allocate+upload+produce in a single function MakeTextFrameForCast. It should be trivial to change to explicit allocation + import + upload.