diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 357578b..c730d67 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -123,6 +123,9 @@
 #include "Client.h"
 #include "ResamplerBufferProvider.h"
 
+// TODO(b/291319167) remove me when AudioFlinger class not directly used by subcomponents
+namespace android { class AudioFlinger; }
+
 // include AudioFlinger component interfaces
 #include "IAfPatchPanel.h"  // this should be listed before other IAf* interfaces.
 #include "IAfEffect.h"
@@ -161,10 +164,10 @@
 
 class AudioFlinger
     : public AudioFlingerServerAdapter::Delegate  // IAudioFlinger client interface
+    , public IAfClientCallback
 {
     friend class sp<AudioFlinger>;
     // TODO(b/291319167) Create interface and remove friends.
-    friend class Client; // removeClient_l();
     friend class DeviceEffectManager;
     friend class DeviceEffectManagerCallback;
     friend class MelReporter;
@@ -358,6 +361,18 @@
 
     // ---- end of IAudioFlinger interface
 
+    // ---- begin IAfClientCallback interface
+
+    Mutex& clientMutex() const final { return mClientLock; }
+    void removeClient_l(pid_t pid) final;
+    void removeNotificationClient(pid_t pid) final;
+    status_t moveAuxEffectToIo(
+            int effectId,
+            const sp<IAfPlaybackThread>& dstThread,
+            sp<IAfPlaybackThread>* srcThread) final;
+
+    // ---- end of IAfClientCallback interface
+
     bool isAudioPolicyReady() const { return mAudioPolicyReady.load(); }
 
     /* List available audio ports and their attributes */
@@ -655,12 +670,6 @@
               status_t moveEffectChain_l(audio_session_t sessionId,
             IAfPlaybackThread* srcThread, IAfPlaybackThread* dstThread);
 
-public:
-    // TODO(b/291319167) cluster together
-              status_t moveAuxEffectToIo(int EffectId,
-            const sp<IAfPlaybackThread>& dstThread, sp<IAfPlaybackThread>* srcThread);
-private:
-
               // return thread associated with primary hardware device, or NULL
               IAfPlaybackThread* primaryPlaybackThread_l() const;
               DeviceTypeSet primaryOutputDevice_l() const;
@@ -677,9 +686,6 @@
                       IAfPlaybackThread* thread,
                       const std::vector<audio_io_handle_t>& secondaryOutputs) const;
 
-
-                void        removeClient_l(pid_t pid);
-                void        removeNotificationClient(pid_t pid);
 public:
     // TODO(b/291319167) cluster together
                 bool isNonOffloadableGlobalEffectEnabled_l();
@@ -731,9 +737,9 @@
                 // must be locked after mLock and ThreadBase::mLock if both must be locked
                 // avoids acquiring AudioFlinger::mLock from inside thread loop.
 
-    // TODO(b/291319167) access by getter,
-    mutable     Mutex                               mClientLock;
 private:
+    mutable Mutex mClientLock;
+
                 // protected by mClientLock
                 DefaultKeyedVector< pid_t, wp<Client> >     mClients;   // see ~Client()