audio: Provide code for parsing surround sound config from XML

The main change is to convert the result of parsing from XSDC
types to AIDL, and add a VTS test for IConfig.getSurroundSoundConfig.

Extra changes:
  - add 'Unchecked' suffix to conversion functions that do not
    wrap the result into ConversionResult;
  - enable more compile-time checks for the default AIDL service,
    fix issues found.

Bug: 205884982
Test: atest VtsHalAudioCoreTargetTest
Change-Id: Icf578b8d28647e6355ed5328599c77d2ca1234f9
diff --git a/audio/aidl/default/Config.cpp b/audio/aidl/default/Config.cpp
index e87af07..d1023da 100644
--- a/audio/aidl/default/Config.cpp
+++ b/audio/aidl/default/Config.cpp
@@ -27,9 +27,16 @@
 
 namespace aidl::android::hardware::audio::core {
 ndk::ScopedAStatus Config::getSurroundSoundConfig(SurroundSoundConfig* _aidl_return) {
-    SurroundSoundConfig surroundSoundConfig;
-    // TODO: parse from XML; for now, use empty config as default
-    *_aidl_return = std::move(surroundSoundConfig);
+    static const SurroundSoundConfig surroundSoundConfig = [this]() {
+        SurroundSoundConfig surroundCfg;
+        if (mAudioPolicyConverter.getStatus() == ::android::OK) {
+            surroundCfg = mAudioPolicyConverter.getSurroundSoundConfig();
+        } else {
+            LOG(WARNING) << __func__ << mAudioPolicyConverter.getError();
+        }
+        return surroundCfg;
+    }();
+    *_aidl_return = surroundSoundConfig;
     LOG(DEBUG) << __func__ << ": returning " << _aidl_return->toString();
     return ndk::ScopedAStatus::ok();
 }