LibWebView+WebContent: Use Web::InputEvent for WebContent input IPC

Now that all input events are handled by LibWebView, replace the IPCs
which send the fields of Web::KeyEvent / Web::MouseEvent individually
with one IPC per event type (key or mouse).

We can also replace the ad-hoc queued input structure with a smaller
struct that simply holds the tranferred Web::KeyEvent / Web::MouseEvent.

In the future, we can also adapt Web::EventHandler to use these structs.

Userland/Libraries/LibWeb/Page/InputEvent.cpp

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibIPC/Decoder.h>
+#include <LibIPC/Encoder.h>
+#include <LibWeb/Page/InputEvent.h>
+
+namespace Web {
+
+KeyEvent KeyEvent::clone_without_chrome_data() const
+{
+    return { type, key, modifiers, code_point, nullptr };
+}
+
+MouseEvent MouseEvent::clone_without_chrome_data() const
+{
+    return { type, position, screen_position, button, buttons, modifiers, wheel_delta_x, wheel_delta_y, nullptr };
+}
+
+}
+
+template<>
+ErrorOr<void> IPC::encode(Encoder& encoder, Web::KeyEvent const& event)
+{
+    TRY(encoder.encode(event.type));
+    TRY(encoder.encode(event.key));
+    TRY(encoder.encode(event.modifiers));
+    TRY(encoder.encode(event.code_point));
+    return {};
+}
+
+template<>
+ErrorOr<Web::KeyEvent> IPC::decode(Decoder& decoder)
+{
+    auto type = TRY(decoder.decode<Web::KeyEvent::Type>());
+    auto key = TRY(decoder.decode<KeyCode>());
+    auto modifiers = TRY(decoder.decode<KeyModifier>());
+    auto code_point = TRY(decoder.decode<u32>());
+
+    return Web::KeyEvent { type, key, modifiers, code_point, nullptr };
+}
+
+template<>
+ErrorOr<void> IPC::encode(Encoder& encoder, Web::MouseEvent const& event)
+{
+    TRY(encoder.encode(event.type));
+    TRY(encoder.encode(event.position));
+    TRY(encoder.encode(event.screen_position));
+    TRY(encoder.encode(event.button));
+    TRY(encoder.encode(event.buttons));
+    TRY(encoder.encode(event.modifiers));
+    TRY(encoder.encode(event.wheel_delta_x));
+    TRY(encoder.encode(event.wheel_delta_y));
+    return {};
+}
+
+template<>
+ErrorOr<Web::MouseEvent> IPC::decode(Decoder& decoder)
+{
+    auto type = TRY(decoder.decode<Web::MouseEvent::Type>());
+    auto position = TRY(decoder.decode<Web::DevicePixelPoint>());
+    auto screen_position = TRY(decoder.decode<Web::DevicePixelPoint>());
+    auto button = TRY(decoder.decode<GUI::MouseButton>());
+    auto buttons = TRY(decoder.decode<GUI::MouseButton>());
+    auto modifiers = TRY(decoder.decode<KeyModifier>());
+    auto wheel_delta_x = TRY(decoder.decode<int>());
+    auto wheel_delta_y = TRY(decoder.decode<int>());
+
+    return Web::MouseEvent { type, position, screen_position, button, buttons, modifiers, wheel_delta_x, wheel_delta_y, nullptr };
+}