Merge "Update documentation for MediaCodec onFrameRendered" into udc-dev

         * Called when an output frame has rendered on the output surface.

         * <p>

         * <strong>Note:</strong> This callback is for informational purposes only: to get precise

         * render timing samples, and can be significantly delayed and batched. Some frames may have

         * been rendered even if there was no callback generated.

         * render timing samples, and can be significantly delayed and batched. Starting with

         * Android {@link android.os.Build.VERSION_CODES#UPSIDE_DOWN_CAKE}, a callback will always

         * be received for each rendered frame providing the MediaCodec is still in the executing

         * state when the callback is dispatched. Prior to Android

         * {@link android.os.Build.VERSION_CODES#UPSIDE_DOWN_CAKE}, some frames may have been

         * rendered even if there was no callback generated.

         *

         * @param codec the MediaCodec instance

         * @param presentationTimeUs the presentation time (media time) of the frame rendered.