LibWeb+LibWebView+WebContent: Add an Inspector IDL object to the Window

This is an internal object that must be explicitly enabled by the chrome
before it is added to the Window. The Inspector object will be used by a
special WebView that will replace all chrome-specific inspector windows.
The IDL defines methods that this WebView will need to inform the chrome
of various events, such as the user clicking a DOM node.

Userland/Libraries/LibWeb/Internals/Inspector.cpp

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Realm.h>
+#include <LibJS/Runtime/VM.h>
+#include <LibWeb/Bindings/InspectorPrototype.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/CSS/Selector.h>
+#include <LibWeb/HTML/BrowsingContext.h>
+#include <LibWeb/HTML/Window.h>
+#include <LibWeb/Internals/Inspector.h>
+#include <LibWeb/Page/Page.h>
+
+namespace Web::Internals {
+
+JS_DEFINE_ALLOCATOR(Inspector);
+
+Inspector::Inspector(JS::Realm& realm)
+    : Bindings::PlatformObject(realm)
+{
+}
+
+Inspector::~Inspector() = default;
+
+void Inspector::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    Object::set_prototype(&Bindings::ensure_web_prototype<Bindings::InspectorPrototype>(realm, "Inspector"));
+}
+
+void Inspector::inspector_loaded()
+{
+    if (auto* page = global_object().browsing_context()->page())
+        page->client().inspector_did_load();
+}
+
+void Inspector::inspect_dom_node(i32 node_id, Optional<i32> const& pseudo_element)
+{
+    if (auto* page = global_object().browsing_context()->page()) {
+        page->client().inspector_did_select_dom_node(node_id, pseudo_element.map([](auto value) {
+            VERIFY(value < to_underlying(Web::CSS::Selector::PseudoElement::PseudoElementCount));
+            return static_cast<Web::CSS::Selector::PseudoElement>(value);
+        }));
+    }
+}
+
+}

Userland/Libraries/LibWeb/Internals/Inspector.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Forward.h>
+#include <LibWeb/Bindings/PlatformObject.h>
+
+namespace Web::Internals {
+
+class Inspector final : public Bindings::PlatformObject {
+    WEB_PLATFORM_OBJECT(Inspector, Bindings::PlatformObject);
+    JS_DECLARE_ALLOCATOR(Inspector);
+
+public:
+    virtual ~Inspector() override;
+
+    void inspector_loaded();
+    void inspect_dom_node(i32 node_id, Optional<i32> const& pseudo_element);
+
+private:
+    explicit Inspector(JS::Realm&);
+
+    virtual void initialize(JS::Realm&) override;
+};
+
+}

Userland/Libraries/LibWeb/Internals/Inspector.idl

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+[Exposed=Nobody] interface Inspector {
+
+    undefined inspectorLoaded();
+    undefined inspectDOMNode(long nodeID, optional long pseudoElement);
+
+};