Bluetooth: A2DP sink interface for Audio Focus change and AVRCP 1.3

 - Add interface to report audio focus change from Bluetooth Apk
   to media task for A2DP Sink scenarios.
 - Add interface to request audiofocus from system/bt.
 - Add interfaces for AVRCP 1.3.

Change-Id: I687ea7be460b3ee3b082db9264621e2e24d04c0c
diff --git a/include/hardware/bt_av.h b/include/hardware/bt_av.h
index 5252a17..5f7601e 100644
--- a/include/hardware/bt_av.h
+++ b/include/hardware/bt_av.h
@@ -38,13 +38,13 @@
 /** Callback for connection state change.
  *  state will have one of the values from btav_connection_state_t
  */
-typedef void (* btav_connection_state_callback)(btav_connection_state_t state, 
+typedef void (* btav_connection_state_callback)(btav_connection_state_t state,
                                                     bt_bdaddr_t *bd_addr);
 
 /** Callback for audiopath state change.
  *  state will have one of the values from btav_audio_state_t
  */
-typedef void (* btav_audio_state_callback)(btav_audio_state_t state, 
+typedef void (* btav_audio_state_callback)(btav_audio_state_t state,
                                                bt_bdaddr_t *bd_addr);
 
 /** Callback for audio configuration change.
@@ -57,6 +57,13 @@
                                                 uint32_t sample_rate,
                                                 uint8_t channel_count);
 
+/*
+ * Callback for audio focus request to be used only in
+ * case of A2DP Sink. This is required because we are using
+ * AudioTrack approach for audio data rendering.
+ */
+typedef void (* btav_audio_focus_request_callback)(bt_bdaddr_t *bd_addr);
+
 /** BT-AV callback structure. */
 typedef struct {
     /** set to sizeof(btav_callbacks_t) */
@@ -64,17 +71,18 @@
     btav_connection_state_callback  connection_state_cb;
     btav_audio_state_callback audio_state_cb;
     btav_audio_config_callback audio_config_cb;
+    btav_audio_focus_request_callback audio_focus_request_cb;
 } btav_callbacks_t;
 
-/** 
+/**
  * NOTE:
  *
  * 1. AVRCP 1.0 shall be supported initially. AVRCP passthrough commands
- *    shall be handled internally via uinput 
+ *    shall be handled internally via uinput
  *
  * 2. A2DP data path shall be handled via a socket pipe between the AudioFlinger
  *    android_audio_hw library and the Bluetooth stack.
- * 
+ *
  */
 /** Represents the standard BT-AV interface.
  *  Used for both the A2DP source and sink interfaces.
@@ -96,6 +104,9 @@
 
     /** Closes the interface. */
     void  (*cleanup)( void );
+
+    /** Sends Audio Focus State. */
+    void  (*audio_focus_state)( int focus_state );
 } btav_interface_t;
 
 __END_DECLS