SF: add composer optional features

Test: SF unit tests

Change-Id: I7f177aae58d13e45dfdd54579722cec55dc21a3a
diff --git a/services/surfaceflinger/DisplayHardware/AidlComposerHal.cpp b/services/surfaceflinger/DisplayHardware/AidlComposerHal.cpp
index c9b6144..3bed796 100644
--- a/services/surfaceflinger/DisplayHardware/AidlComposerHal.cpp
+++ b/services/surfaceflinger/DisplayHardware/AidlComposerHal.cpp
@@ -253,6 +253,13 @@
 
 AidlComposer::~AidlComposer() = default;
 
+bool AidlComposer::isSupported(OptionalFeature feature) const {
+    switch (feature) {
+        case OptionalFeature::RefreshRateSwitching:
+            return true;
+    }
+}
+
 std::vector<IComposer::Capability> AidlComposer::getCapabilities() {
     std::vector<Capability> capabilities;
     const auto status = mAidlComposer->getCapabilities(&capabilities);