Camera: implement buffer managment API

Test: compile
Bug: 109829698
Change-Id: I3d95792282da52db9db6fd6a086bbd7b3ff9dca9
diff --git a/services/camera/libcameraservice/device3/Camera3IOStreamBase.cpp b/services/camera/libcameraservice/device3/Camera3IOStreamBase.cpp
index 3c1e43d..18b8c4d 100644
--- a/services/camera/libcameraservice/device3/Camera3IOStreamBase.cpp
+++ b/services/camera/libcameraservice/device3/Camera3IOStreamBase.cpp
@@ -116,7 +116,7 @@
     return mTotalBufferCount;
 }
 
-size_t Camera3IOStreamBase::getHandoutOutputBufferCountLocked() {
+size_t Camera3IOStreamBase::getHandoutOutputBufferCountLocked() const {
     return mHandoutOutputBufferCount;
 }