Move the VST3 context menu target implementation

So it can also be used on the Wine side in a bit.

src/common/serialization/vst3-impls/context-menu-target.h

@@ -0,0 +1,57 @@
+// yabridge: a Wine VST bridge
+// Copyright (C) 2020-2022 Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include "../vst3/context-menu-target.h"
+
+/**
+ * This implementation used to live in `src/plugin/bridges/vst3-impls`, but
+ * since plugins can also call context menu items added by the host this is
+ * needed on both sides.
+ */
+template <typename Bridge>
+class YaContextMenuTargetImpl : public YaContextMenuTarget {
+   public:
+    YaContextMenuTargetImpl(Bridge& bridge, ConstructArgs&& args) noexcept
+        : YaContextMenuTarget(std::move(args)), bridge_(bridge) {}
+
+    /**
+     * We'll override the query interface to log queries for interfaces we do
+     * not (yet) support.
+     */
+    tresult PLUGIN_API queryInterface(const Steinberg::TUID _iid,
+                                      void** obj) override {
+        const tresult result = YaContextMenuTarget::queryInterface(_iid, obj);
+        bridge_.logger_.log_query_interface(
+            "In IContextMenuTarget::queryInterface()", result,
+            Steinberg::FUID::fromTUID(_iid));
+
+        return result;
+    }
+
+    // From `IContextMenuTarget`
+    tresult PLUGIN_API executeMenuItem(int32 tag) override {
+        return bridge_.send_message(YaContextMenuTarget::ExecuteMenuItem{
+            .owner_instance_id = owner_instance_id(),
+            .context_menu_id = context_menu_id(),
+            .target_tag = target_tag(),
+            .tag = tag});
+    }
+
+   private:
+    Bridge& bridge_;
+};