audio: Make renamings suggested by reviewers

Rename DriverInterface::getPosition -> refinePosition. This reflects
the fact that the driver may provide more precise position, however
this is an optional operation.

Rename StreamIn/Out::mContext -> mContextInstance. This is
to emphasize that StreamIn/Out actually own the context and they
hold the real context instance, not just a reference/pointer
to it, like other classes involved in the inheritance chain.

Bug: 286914845
Test: atest VtsHalAudioCoreTargetTest
Change-Id: Id7159f9bf3ee020dc7cf594ec35f5d59d23d7e31
diff --git a/audio/aidl/default/usb/StreamUsb.cpp b/audio/aidl/default/usb/StreamUsb.cpp
index 9684a87..4efe0d8 100644
--- a/audio/aidl/default/usb/StreamUsb.cpp
+++ b/audio/aidl/default/usb/StreamUsb.cpp
@@ -85,7 +85,7 @@
 
 StreamInUsb::StreamInUsb(StreamContext&& context, const SinkMetadata& sinkMetadata,
                          const std::vector<MicrophoneInfo>& microphones)
-    : StreamIn(std::move(context), microphones), StreamUsb(&(StreamIn::mContext), sinkMetadata) {}
+    : StreamIn(std::move(context), microphones), StreamUsb(&mContextInstance, sinkMetadata) {}
 
 ndk::ScopedAStatus StreamInUsb::getActiveMicrophones(
         std::vector<MicrophoneDynamicInfo>* _aidl_return __unused) {
@@ -96,7 +96,7 @@
 StreamOutUsb::StreamOutUsb(StreamContext&& context, const SourceMetadata& sourceMetadata,
                            const std::optional<AudioOffloadInfo>& offloadInfo)
     : StreamOut(std::move(context), offloadInfo),
-      StreamUsb(&(StreamOut::mContext), sourceMetadata),
+      StreamUsb(&mContextInstance, sourceMetadata),
       mChannelCount(getChannelCount(getContext().getChannelLayout())) {}
 
 ndk::ScopedAStatus StreamOutUsb::getHwVolume(std::vector<float>* _aidl_return) {