Add stubs for IXmlRepresentationController

src/plugin/bridges/vst3-impls/plugin-proxy.cpp

@@ -788,3 +788,12 @@ Vst3PluginProxyImpl::setUnitProgramData(int32 listOrUnitId,
                                        .program_index = programIndex,
                                        .data = data});
 }
+
+tresult PLUGIN_API Vst3PluginProxyImpl::getXmlRepresentationStream(
+    Steinberg::Vst::RepresentationInfo& info /*in*/,
+    Steinberg::IBStream* stream /*out*/) {
+    // TODO: Implement
+    bridge.logger.log(
+        "TODO: IXmlRepresentationController::getXmlRepresentationStream()");
+    return Steinberg::kNotImplemented;
+}

src/plugin/bridges/vst3-impls/plugin-proxy.h

@@ -244,6 +244,11 @@ class Vst3PluginProxyImpl : public Vst3PluginProxy {
                                           int32 programIndex,
                                           Steinberg::IBStream* data) override;
 
+    // From `IXmlRepresentationController`
+    tresult PLUGIN_API
+    getXmlRepresentationStream(Steinberg::Vst::RepresentationInfo& info /*in*/,
+                               Steinberg::IBStream* stream /*out*/);
+
     /**
      * The component handler the host passed to us during
      * `IEditController::setComponentHandler()`. When the plugin makes a