Wrapper around audio HALs that are compiled against the ICS API.

Makes it possible to build a ROM without ICS_AUDIO_BLOB set or other workarounds
in the framework. Parts of the Android framework are backwards compatible with
audio HALs that only implement the ICS API. The audio HAL API however is not
designed to be ABI compatible and a recompilation would be necessary (well with
adjustments). Since we cannot do that we need to either add support for it into
the framework (ICS_AUDIO_BLOB / MR0_AUDIO_BLOB) or wrap the audio HALs.

The wrapper does the following things:
   * wraps audio_policy and audio.primary HALs
   * wraps audio_policy_service_ops
   * converts audio_devices_t enum between Android <=4.1 and >= 4.2 APIs

When the primary audio HAL is wrapped it is possible to use a stock audio policy
and A2DP HAL (at least in case of endeavoru). This fixes a couple of bugs
related to incorrect stream volumes and moving streams between devices.


Confiuration
------------

See config.mk for possible configuration variables.


TODO
----

* Grep for TODO :)
* Better logging configurability (maybe at runtime)
* Expects the vendor blobs to be named vendor-audio_policy.tegra.so and
  vendor-audio.primary.tegra.so at the moment.
* More testing


Known Issues
------------

* set_stream_volume_index_for_device is not properly emulated resulting in wrong
  volumes for streams after the device is rebooted. This is caused by
  AudioFlinger setting the volumes for each stream on each device. Since the
  function is not properly implemented the value of the last device will be
  used as the initial volume.
  See StreamState.applyAllVolumes in AudioService.java.
  Framework workaround for headset/speaker devices: http://review.cyanogenmod.org/#/c/33778/
* The code in AudioFlinger::findSuitableHwDev_l that compares wanted devices
  against the output of the wrapped get_supported_devices() function will not
  properly work because the old audio_devices_t flags could represent input
  and output devices independently. Now it's not possible anymore.
  If that is confusing then look at the flags table below. For example how to
  specify that only AUDIO_DEVICE_OUT_EARPIECE and AUDIO_DEVICE_IN_VOICE_CALL
  is supported without implicitly supporting AUDIO_DEVICE_IN_COMMUNICATION
  and AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT.
  get_supported_devices for the endeavoru ICS blob returns
  0x8ff8607f_16 = 10001111111110000110000001111111_2 which seems weird anyway.


Misc
----

Catch interesing output:

    $ adb logcat -s AudioFlinger:D AudioPolicyServiceWrapper:D AudioWrapper:D AudioPolicyWrapper:D AudioWrapperCommon:D


Flags
-----

Following table lists the audio_devices enum values.

Bit Nr. Hex Value API <= 4.1                                 API >= 4.2 output devices                  API >= 4.2 input devices
------- --------- ------------------------------------------ ------------------------------------------ ------------------------------------

31      80000000  AUDIO_DEVICE_IN_DEFAULT                                                               AUDIO_DEVICE_BIT_IN
30      40000000                                             AUDIO_DEVICE_OUT_DEFAULT                   AUDIO_DEVICE_IN_DEFAULT
29      20000000
28      10000000
27      8000000
26      4000000
25      2000000
24      1000000
23      800000    AUDIO_DEVICE_IN_BACK_MIC
22      400000    AUDIO_DEVICE_IN_VOICE_CALL
21      200000    AUDIO_DEVICE_IN_AUX_DIGITAL
20      100000    AUDIO_DEVICE_IN_WIRED_HEADSET
19      80000     AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET
18      40000     AUDIO_DEVICE_IN_BUILTIN_MIC
17      20000     AUDIO_DEVICE_IN_AMBIENT
16      10000     AUDIO_DEVICE_IN_COMMUNICATION
15      8000      AUDIO_DEVICE_OUT_DEFAULT                   AUDIO_DEVICE_OUT_REMOTE_SUBMIX
14      4000      AUDIO_DEVICE_OUT_USB_DEVICE                AUDIO_DEVICE_OUT_USB_DEVICE
13      2000      AUDIO_DEVICE_OUT_USB_ACCESSORY             AUDIO_DEVICE_OUT_USB_ACCESSORY
12      1000      AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET         AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET         AUDIO_DEVICE_IN_USB_DEVICE
11      800       AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET         AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET         AUDIO_DEVICE_IN_USB_ACCESSORY
10      400       AUDIO_DEVICE_OUT_AUX_DIGITAL               AUDIO_DEVICE_OUT_AUX_DIGITAL               AUDIO_DEVICE_IN_DGTL_DOCK_HEADSET
9       200       AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER    AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER    AUDIO_DEVICE_IN_ANLG_DOCK_HEADSET
8       100       AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES AUDIO_DEVICE_IN_REMOTE_SUBMIX
7       80        AUDIO_DEVICE_OUT_BLUETOOTH_A2DP            AUDIO_DEVICE_OUT_BLUETOOTH_A2DP            AUDIO_DEVICE_IN_BACK_MIC
6       40        AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT      AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT      AUDIO_DEVICE_IN_VOICE_CALL
5       20        AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET     AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET     AUDIO_DEVICE_IN_AUX_DIGITAL
4       10        AUDIO_DEVICE_OUT_BLUETOOTH_SCO             AUDIO_DEVICE_OUT_BLUETOOTH_SCO             AUDIO_DEVICE_IN_WIRED_HEADSET
3       8         AUDIO_DEVICE_OUT_WIRED_HEADPHONE           AUDIO_DEVICE_OUT_WIRED_HEADPHONE           AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET
2       4         AUDIO_DEVICE_OUT_WIRED_HEADSET             AUDIO_DEVICE_OUT_WIRED_HEADSET             AUDIO_DEVICE_IN_BUILTIN_MIC
1       2         AUDIO_DEVICE_OUT_SPEAKER                   AUDIO_DEVICE_OUT_SPEAKER                   AUDIO_DEVICE_IN_AMBIENT
0       1         AUDIO_DEVICE_OUT_EARPIECE                  AUDIO_DEVICE_OUT_EARPIECE                  AUDIO_DEVICE_IN_COMMUNICATION