[2/3] FW AV: Audio Theme Support

From: https://gerrit.omnirom.org/#/c/5244/

Original commit message:

 On the Java side, Android has support for both a
 Video Record Start sound, and a different Video
 Record Stop sound. However, this part here only
 supports one video recording sound.
 We added support for RECORDING_STOP sound (by default,
 the same as RECORDING).

Change-Id: Ib5c1b3b76ff91518c7c7c6a0601a9e80a73ce4d1
DataSource: Split off ffmpeg sniffer to a second pass, and only if necessary

ffmpeg's sniffer is intended as a grab-all-that-doesn't-work-elsewhere
extractor. Unfortunately, this causes two issues:

- As written, it requires ffmpeg to whitelist any extractors supported
by stagefright, or else it will blindly override them. This has codebase
sync issues, as shown by the VP9 and WAV accidental overrides
- It imposes an in-depth analysis of _all_ media, even that which we
want to be processed quickly by shipping stagefright plugins (hardware
or not). This is mostly noticeable in network streams and thumbnail
generation.

This patch moves FFmpegExtractor to an independent sniffer queue, and
it only invokes it when the regular MediaExtractor hits 1 of 3 conditions:

1 - The confidence in the identified container type is low
2 - No container is identified at all
3 - A video container was found by other extractors, but only 1 stream
(audio or video) was identified.

Change-Id: Ib96ff4f6bc06223fe0e819a57560d3c872a79ddd
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_frameworks_av into kitkat