Introduce CaptureStateNotifier

This is a helper class for notifying a client of capture
state changes.

Bug: 146157104
Test: Compiles (further testing as part of the topic).
Merged-In: Ie27bc404805d319a6969290a6369d59fb68c1f38
Change-Id: I2902468c4692ba68e4bc9be0e5038d5505da7154
diff --git a/media/libaudioclient/Android.bp b/media/libaudioclient/Android.bp
index 65afc8d..0ec63b9 100644
--- a/media/libaudioclient/Android.bp
+++ b/media/libaudioclient/Android.bp
@@ -21,6 +21,7 @@
         "AudioVolumeGroup.cpp",
     ],
     shared_libs: [
+        "capture_state_listener-aidl-cpp",
         "libaudiofoundation",
         "libaudioutils",
         "libbinder",
@@ -34,6 +35,9 @@
     ],
     include_dirs: ["system/media/audio_utils/include"],
     export_include_dirs: ["include"],
+    export_shared_lib_headers: [
+        "capture_state_listener-aidl-cpp",
+    ],
 }
 
 cc_library_shared {
@@ -148,3 +152,11 @@
     ],
     path: "aidl",
 }
+
+aidl_interface {
+    name: "capture_state_listener-aidl",
+    local_include_dir: "aidl",
+    srcs: [
+        "aidl/android/media/ICaptureStateListener.aidl",
+    ],
+}