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/Services/WebContent/ConnectionFromClient.cpp

@@ -929,4 +929,9 @@ void ConnectionFromClient::inspect_accessibility_tree()
     }
 }
 
+void ConnectionFromClient::enable_inspector_prototype()
+{
+    Web::HTML::Window::set_inspector_object_exposed(true);
+}
+
 }