LibWebView: Define the list of built-in search engines in LibWebView

These engines and their query URLs are duplicated in several places.
Before implementing search support in the AppKit chrome, let's move
these engines to LibWebView.

Userland/Libraries/LibWebView/SearchEngine.cpp

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Find.h>
+#include <LibWebView/SearchEngine.h>
+
+namespace WebView {
+
+static constexpr auto builtin_search_engines = Array {
+    SearchEngine { "Bing"sv, "https://www.bing.com/search?q={}"sv },
+    SearchEngine { "Brave"sv, "https://search.brave.com/search?q={}"sv },
+    SearchEngine { "DuckDuckGo"sv, "https://duckduckgo.com/?q={}"sv },
+    SearchEngine { "GitHub"sv, "https://github.com/search?q={}"sv },
+    SearchEngine { "Google"sv, "https://www.google.com/search?q={}"sv },
+    SearchEngine { "Mojeek"sv, "https://www.mojeek.com/search?q={}"sv },
+    SearchEngine { "Yahoo"sv, "https://search.yahoo.com/search?p={}"sv },
+    SearchEngine { "Yandex"sv, "https://yandex.com/search/?text={}"sv },
+};
+
+ReadonlySpan<SearchEngine> search_engines()
+{
+    return builtin_search_engines;
+}
+
+SearchEngine const& default_search_engine()
+{
+    static auto default_engine = find_search_engine("Google"sv);
+    VERIFY(default_engine.has_value());
+
+    return *default_engine;
+}
+
+Optional<SearchEngine const&> find_search_engine(StringView name)
+{
+    auto it = AK::find_if(builtin_search_engines.begin(), builtin_search_engines.end(),
+        [&](auto const& engine) {
+            return engine.name == name;
+        });
+
+    if (it == builtin_search_engines.end())
+        return {};
+
+    return *it;
+}
+
+}