LibWeb: Stub out all the functions from the execCommand spec

Per the specification, it's ok if we say that nothing is supported.

It's not ok if we say something is supported but do nothing, apparently.

Tests/LibWeb/Text/expected/Editing/execCommand-is-a-noop.txt

@@ -0,0 +1,7 @@
+Hello, world!I'm totally bold rn  execCommand("bold") returned false
+Hello, world!<b>I'm totally bold rn</b>
+queryCommandEnabled("bold") returned false
+queryCommandIndeterm("bold") returned false
+queryCommandState("bold") returned false
+queryCommandSupported("bold") returned false
+queryCommandValue("bold") returned ""

Tests/LibWeb/Text/input/Editing/execCommand-is-a-noop.html

@@ -0,0 +1,32 @@
+<script src="../include.js"></script>
+<div id="text" contenteditable="true"></div>
+<script>
+    test(() => {
+        let text = document.getElementById("text");
+        text.focus();
+
+        let hello = text.appendChild(document.createTextNode("Hello, world!"));
+
+        let boldText = document.createTextNode("I'm totally bold rn");
+        let boldTag = text.appendChild(document.createElement("b"));
+        boldTag.appendChild(boldText);
+
+        // select the text
+        let range = document.createRange();
+        range.selectNodeContents(hello);
+        let selection = window.getSelection();
+        selection.removeAllRanges();
+        selection.addRange(range);
+
+        let e = document.execCommand("bold", false, "on");
+        println(`execCommand("bold") returned ${e}`);
+        let allTheText = text.innerHTML;
+        println(allTheText);
+
+        println(`queryCommandEnabled("bold") returned ${document.queryCommandEnabled("bold")}`);
+        println(`queryCommandIndeterm("bold") returned ${document.queryCommandIndeterm("bold")}`);
+        println(`queryCommandState("bold") returned ${document.queryCommandState("bold")}`);
+        println(`queryCommandSupported("bold") returned ${document.queryCommandSupported("bold")}`);
+        println(`queryCommandValue("bold") returned "${document.queryCommandValue("bold")}"`);
+    });
+</script>

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -2987,13 +2987,6 @@ void Document::did_stop_being_active_document_in_navigable()
     }
 }
 
-// https://w3c.github.io/editing/docs/execCommand/#querycommandsupported()
-bool Document::query_command_supported(String const& command) const
-{
-    dbgln("(STUBBED) Document::query_command_supported(command='{}')", command);
-    return false;
-}
-
 void Document::increment_throw_on_dynamic_markup_insertion_counter(Badge<HTML::HTMLParser>)
 {
     ++m_throw_on_dynamic_markup_insertion_counter;
@@ -4076,4 +4069,40 @@ WebIDL::ExceptionOr<JS::Value> Document::named_item_value(FlyString const& name)
     return collection;
 }
 
+// https://w3c.github.io/editing/docs/execCommand/#execcommand()
+bool Document::exec_command(String, bool, String)
+{
+    return false;
+}
+
+// https://w3c.github.io/editing/docs/execCommand/#querycommandenabled()
+bool Document::query_command_enabled(String)
+{
+    return false;
+}
+
+// https://w3c.github.io/editing/docs/execCommand/#querycommandindeterm()
+bool Document::query_command_indeterm(String)
+{
+    return false;
+}
+
+// https://w3c.github.io/editing/docs/execCommand/#querycommandstate()
+bool Document::query_command_state(String)
+{
+    return false;
+}
+
+// https://w3c.github.io/editing/docs/execCommand/#querycommandsupported()
+bool Document::query_command_supported(String)
+{
+    return false;
+}
+
+// https://w3c.github.io/editing/docs/execCommand/#querycommandvalue()
+String Document::query_command_value(String)
+{
+    return String {};
+}
+
 }

Userland/Libraries/LibWeb/DOM/Document.h

@@ -500,12 +500,18 @@ public:
     DocumentUnloadTimingInfo const& previous_document_unload_timing() const { return m_previous_document_unload_timing; }
     void set_previous_document_unload_timing(DocumentUnloadTimingInfo const& previous_document_unload_timing) { m_previous_document_unload_timing = previous_document_unload_timing; }
 
+    // https://w3c.github.io/editing/docs/execCommand/
+    bool exec_command(String command_id, bool show_ui, String value);
+    bool query_command_enabled(String command_id);
+    bool query_command_indeterm(String command_id);
+    bool query_command_state(String command_id);
+    bool query_command_supported(String command_id);
+    String query_command_value(String command_id);
+
     bool is_allowed_to_use_feature(PolicyControlledFeature) const;
 
     void did_stop_being_active_document_in_navigable();
 
-    bool query_command_supported(String const&) const;
-
     String dump_accessibility_tree_as_json();
 
     void make_active();

Userland/Libraries/LibWeb/DOM/Document.idl

@@ -106,7 +106,6 @@ interface Document : Node {
 
     [CEReactions] attribute DOMString title;
 
-    boolean queryCommandSupported(DOMString commandId);
     readonly attribute boolean hidden;
     readonly attribute DOMString visibilityState;
 
@@ -124,6 +123,14 @@ interface Document : Node {
     Element? elementFromPoint(double x, double y);
     sequence<Element> elementsFromPoint(double x, double y);
     readonly attribute Element? scrollingElement;
+
+    // https://w3c.github.io/editing/docs/execCommand/
+    [CEReactions] boolean execCommand(DOMString commandId, optional boolean showUI = false, optional DOMString value = "");
+    boolean queryCommandEnabled(DOMString commandId);
+    boolean queryCommandIndeterm(DOMString commandId);
+    boolean queryCommandState(DOMString commandId);
+    boolean queryCommandSupported(DOMString commandId);
+    DOMString queryCommandValue(DOMString commandId);
 };
 
 dictionary ElementCreationOptions {