LibWeb: Move automatic browsing context creation to HTMLIFrameElement

We will soon have two DOM nodes which contain nested browsing contexts:
HTMLIFrameElement and HTMLObjectElement. Only HTMLIFrameElement should
have its nested context created automatically upon insertion, so move
the invocation of that logic to HTMLIFrameElement.

Userland/Libraries/LibWeb/HTML/BrowsingContextContainer.cpp

@@ -21,25 +21,38 @@ BrowsingContextContainer::BrowsingContextContainer(DOM::Document& document, DOM:
 
 BrowsingContextContainer::~BrowsingContextContainer() = default;
 
-void BrowsingContextContainer::inserted()
+// https://html.spec.whatwg.org/multipage/browsers.html#creating-a-new-nested-browsing-context
+void BrowsingContextContainer::create_new_nested_browsing_context()
 {
-    HTMLElement::inserted();
-    if (!is_connected())
+    // 1. Let group be element's node document's browsing context's top-level browsing context's group.
+    // FIXME: We do not have a concept of "browsing context groups" yet.
+    auto* group = document().browsing_context();
+    if (!group)
         return;
-    if (auto* browsing_context = document().browsing_context()) {
-        VERIFY(browsing_context->page());
-        m_nested_browsing_context = BrowsingContext::create_nested(*browsing_context->page(), *this);
-        browsing_context->append_child(*m_nested_browsing_context);
-        m_nested_browsing_context->set_frame_nesting_levels(browsing_context->frame_nesting_levels());
-        m_nested_browsing_context->register_frame_nesting(document().url());
-    }
+
+    VERIFY(group->page());
+
+    // 2. Let browsingContext be the result of creating a new browsing context with element's node document, element, and group.
+    // 3. Set element's nested browsing context to browsingContext.
+    m_nested_browsing_context = BrowsingContext::create_nested(*group->page(), *this);
+    group->append_child(*m_nested_browsing_context);
+    m_nested_browsing_context->set_frame_nesting_levels(group->frame_nesting_levels());
+    m_nested_browsing_context->register_frame_nesting(document().url());
+
+    // 4. If element has a name attribute, then set browsingContext's name to the value of this attribute.
+    if (auto name = attribute(HTML::AttributeNames::name); !name.is_empty())
+        m_nested_browsing_context->set_name(name);
 }
 
-void BrowsingContextContainer::removed_from(Node* old_parent)
+// https://html.spec.whatwg.org/multipage/window-object.html#a-browsing-context-is-discarded
+void BrowsingContextContainer::discard_nested_browsing_context()
 {
-    HTMLElement::removed_from(old_parent);
+    // 1. Discard all Document objects for all the entries in browsingContext's session history.
     if (m_nested_browsing_context && m_nested_browsing_context->parent())
         m_nested_browsing_context->parent()->remove_child(*m_nested_browsing_context);
+
+    // 2. If browsingContext is a top-level browsing context, then remove browsingContext.
+    // NOTE: We skip this here because this is by definition a nested browsing context, not top-level.
 }
 
 // https://html.spec.whatwg.org/multipage/browsers.html#concept-bcc-content-document
@@ -55,7 +68,7 @@ const DOM::Document* BrowsingContextContainer::content_document() const
     // 3. Let document be context's active document.
     auto const* document = context.active_document();
 
-    //FIXME: This should not be here, as we're expected to have a document at this point.
+    // FIXME: This should not be here, as we're expected to have a document at this point.
     if (!document)
         return nullptr;
 

Userland/Libraries/LibWeb/HTML/BrowsingContextContainer.h

@@ -21,10 +21,10 @@ public:
     const DOM::Document* content_document() const;
     DOM::Document const* content_document_without_origin_check() const;
 
-    virtual void inserted() override;
-    virtual void removed_from(Node*) override;
-
 protected:
+    void create_new_nested_browsing_context();
+    void discard_nested_browsing_context();
+
     RefPtr<BrowsingContext> m_nested_browsing_context;
 
 private:

Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp

@@ -32,11 +32,28 @@ void HTMLIFrameElement::parse_attribute(const FlyString& name, const String& val
         load_src(value);
 }
 
+// https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-iframe-element:the-iframe-element-6
 void HTMLIFrameElement::inserted()
 {
-    BrowsingContextContainer::inserted();
-    if (is_connected())
-        load_src(attribute(HTML::AttributeNames::src));
+    HTMLElement::inserted();
+
+    if (!is_connected())
+        return;
+
+    // 1. Create a new nested browsing context for element.
+    create_new_nested_browsing_context();
+
+    // 2. FIXME: If element has a sandbox attribute, then parse the sandboxing directive given the attribute's value and element's iframe sandboxing flag set.
+
+    // 3. Process the iframe attributes for element, with initialInsertion set to true.
+    load_src(attribute(HTML::AttributeNames::src));
+}
+
+// https://html.spec.whatwg.org/multipage/iframe-embed-object.html#the-iframe-element:the-iframe-element-7
+void HTMLIFrameElement::removed_from(DOM::Node* node)
+{
+    HTMLElement::removed_from(node);
+    discard_nested_browsing_context();
 }
 
 void HTMLIFrameElement::load_src(const String& value)

Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.h

@@ -21,6 +21,7 @@ public:
 
 private:
     virtual void inserted() override;
+    virtual void removed_from(Node*) override;
     virtual void parse_attribute(const FlyString& name, const String& value) override;
 
     void load_src(const String&);