feat: allow GUID parameter to avoid systray demotion on Windows (#21891)

* fix: systray icon demotion

Adding support for GUID parameter in Tray API.
In combination with signed binaries this allows to maintain
the position in the systray on Windows.

* unit tests

* make mac and linux compile

shell/common/gin_converters/guid_converter.h

@@ -0,0 +1,55 @@
+// Copyright (c) 2020 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef SHELL_COMMON_GIN_CONVERTERS_GUID_CONVERTER_H_
+#define SHELL_COMMON_GIN_CONVERTERS_GUID_CONVERTER_H_
+
+#if defined(OS_WIN)
+#include <rpc.h>
+#endif
+#include <string>
+
+#include "gin/converter.h"
+
+#if defined(OS_WIN)
+typedef GUID UUID;
+#else
+typedef struct {
+} UUID;
+#endif
+
+namespace gin {
+
+template <>
+struct Converter<UUID> {
+  static bool FromV8(v8::Isolate* isolate,
+                     v8::Local<v8::Value> val,
+                     UUID* out) {
+#if defined(OS_WIN)
+    std::string guid;
+    if (!gin::ConvertFromV8(isolate, val, &guid))
+      return false;
+
+    UUID uid;
+
+    if (guid.length() > 0) {
+      unsigned char* uid_cstr = (unsigned char*)guid.c_str();
+      RPC_STATUS result = UuidFromStringA(uid_cstr, &uid);
+      if (result == RPC_S_INVALID_STRING_UUID) {
+        return false;
+      } else {
+        *out = uid;
+        return true;
+      }
+    }
+    return false;
+#else
+    return false;
+#endif
+  }
+};
+
+}  // namespace gin
+
+#endif  // SHELL_COMMON_GIN_CONVERTERS_GUID_CONVERTER_H_