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/alsa/StreamAlsa.cpp b/audio/aidl/default/alsa/StreamAlsa.cpp
index 00a7a84..1d22a60 100644
--- a/audio/aidl/default/alsa/StreamAlsa.cpp
+++ b/audio/aidl/default/alsa/StreamAlsa.cpp
@@ -108,7 +108,7 @@
     return ::android::OK;
 }
 
-::android::status_t StreamAlsa::getPosition(StreamDescriptor::Position* position) {
+::android::status_t StreamAlsa::refinePosition(StreamDescriptor::Position* position) {
     if (mAlsaDeviceProxies.empty()) {
         LOG(FATAL) << __func__ << ": no input devices";
         return ::android::NO_INIT;