Add a mechanism to configure the default A2DP codec priorities

Previously, the relative codec priorities were hard-codec internally.
The new mechanism uses the following configurable resources in
packages/apps/Bluetooth/res/values/config.xml to re-assign the
default codec priorities per device, or to explicitly disable a codec.

 - a2dp_source_codec_priority_sbc
 - a2dp_source_codec_priority_aac
 - a2dp_source_codec_priority_aptx
 - a2dp_source_codec_priority_aptx_hd
 - a2dp_source_codec_priority_ldac

Those values are assigned on startup.
Also, they can be changed per device by using an overlay:
device/<VENDOR>/<DEVICE>/overlay/packages/apps/Bluetooth/res/values/config.xml

Test: Manually streaming to a headset
Change-Id: I432174975d7afbecb8f27cb0e55f5aa816c6e64e

1 files changed, 12 insertions, 3 deletions

diff --git a/include/hardware/bt_av.h b/include/hardware/bt_av.h
index 66a8643d..91ae2ace 100644
--- a/include/hardware/bt_av.h
+++ b/include/hardware/bt_av.h
@@ -69,7 +69,15 @@ typedef enum {
 } btav_a2dp_codec_index_t;
 
 typedef enum {
+  // Disable the codec.
+  // NOTE: This value can be used only during initialization when
+  // function btav_source_interface_t::init() is called.
+  BTAV_A2DP_CODEC_PRIORITY_DISABLED = -1,
+
+  // Reset the codec priority to its default value.
   BTAV_A2DP_CODEC_PRIORITY_DEFAULT = 0,
+
+  // Highest codec priority.
   BTAV_A2DP_CODEC_PRIORITY_HIGHEST = 1000 * 1000
 } btav_a2dp_codec_priority_t;
 
@@ -156,7 +164,7 @@ typedef struct {
     btav_audio_source_config_callback audio_config_cb;
 } btav_source_callbacks_t;
 
-/** BT-AV A2DP Source callback structure. */
+/** BT-AV A2DP Sink callback structure. */
 typedef struct {
     /** set to sizeof(btav_sink_callbacks_t) */
     size_t      size;
@@ -183,9 +191,10 @@ typedef struct {
     /** set to sizeof(btav_source_interface_t) */
     size_t          size;
     /**
-     * Register the BtAv callbacks
+     * Register the BtAv callbacks.
      */
-    bt_status_t (*init)( btav_source_callbacks_t* callbacks );
+    bt_status_t (*init)(btav_source_callbacks_t* callbacks,
+                std::vector<btav_a2dp_codec_config_t> codec_priorities);
 
     /** connect to headset */
     bt_status_t (*connect)( bt_bdaddr_t *bd_addr );