LibWeb: Fill-in some fixmes around sandboxing flag sets

...Including a couple of steps in
obtain_a_browsing_context_to_use_for_a_navigation_response() which
didn't have FIXMEs.

No apparent changes on WPT.

Libraries/LibWeb/DOM/Document.cpp

@@ -183,8 +183,10 @@ static GC::Ref<HTML::BrowsingContext> obtain_a_browsing_context_to_use_for_a_nav
         VERIFY(navigation_coop.value == HTML::OpenerPolicyValue::UnsafeNone);
 
         // 2. Assert: newBrowsingContext's popup sandboxing flag set is empty.
+        VERIFY(is_empty(new_browsing_context->popup_sandboxing_flag_set()));
 
         // 3. Set newBrowsingContext's popup sandboxing flag set to a clone of sandboxFlags.
+        new_browsing_context->set_popup_sandboxing_flag_set(sandbox_flags);
     }
 
     // 6. Return newBrowsingContext.
@@ -3215,6 +3217,11 @@ HTML::SandboxingFlagSet Document::active_sandboxing_flag_set() const
     return m_active_sandboxing_flag_set;
 }
 
+void Document::set_active_sandboxing_flag_set(HTML::SandboxingFlagSet sandboxing_flag_set)
+{
+    m_active_sandboxing_flag_set = sandboxing_flag_set;
+}
+
 HTML::PolicyContainer Document::policy_container() const
 {
     return m_policy_container;

Libraries/LibWeb/DOM/Document.h

@@ -526,6 +526,7 @@ class Document
 
     // https://html.spec.whatwg.org/multipage/origin.html#active-sandboxing-flag-set
     HTML::SandboxingFlagSet active_sandboxing_flag_set() const;
+    void set_active_sandboxing_flag_set(HTML::SandboxingFlagSet);
 
     // https://html.spec.whatwg.org/multipage/dom.html#concept-document-policy-container
     HTML::PolicyContainer policy_container() const;

Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -163,7 +163,7 @@ WebIDL::ExceptionOr<BrowsingContext::BrowsingContextAndDocument> BrowsingContext
         browsing_context->m_virtual_browsing_context_group_id = creator->browsing_context()->top_level_browsing_context()->m_virtual_browsing_context_group_id;
     }
 
-    // 6. Let sandboxFlags be the result of determining the creation sandboxing flags given browsingContext and embedder.
+    // FIXME: 6. Let sandboxFlags be the result of determining the creation sandboxing flags given browsingContext and embedder.
     SandboxingFlagSet sandbox_flags = {};
 
     // 7. Let origin be the result of determining the origin given about:blank, sandboxFlags, and creatorOrigin.
@@ -236,7 +236,8 @@ WebIDL::ExceptionOr<BrowsingContext::BrowsingContextAndDocument> BrowsingContext
 
     // FIXME: permissions policy: permissionsPolicy
 
-    // FIXME: active sandboxing flag set: sandboxFlags
+    // active sandboxing flag set: sandboxFlags
+    document->set_active_sandboxing_flag_set(sandbox_flags);
 
     // load timing info: loadTimingInfo
     document->set_load_timing_info(load_timing_info);

Libraries/LibWeb/HTML/BrowsingContext.h

@@ -124,6 +124,10 @@ class BrowsingContext final : public JS::Cell {
 
     // https://html.spec.whatwg.org/multipage/origin.html#one-permitted-sandboxed-navigator
     BrowsingContext const* the_one_permitted_sandboxed_navigator() const;
+    void set_the_one_permitted_sandboxed_navigator(BrowsingContext const*)
+    {
+        // FIXME: Implement this
+    }
 
     bool has_navigable_been_destroyed() const;
 
@@ -132,6 +136,9 @@ class BrowsingContext final : public JS::Cell {
 
     void set_is_popup(TokenizedFeature::Popup is_popup) { m_is_popup = is_popup; }
 
+    SandboxingFlagSet popup_sandboxing_flag_set() const { return m_popup_sandboxing_flag_set; }
+    void set_popup_sandboxing_flag_set(SandboxingFlagSet value) { m_popup_sandboxing_flag_set = value; }
+
 private:
     explicit BrowsingContext(GC::Ref<Page>);
 
@@ -151,6 +158,9 @@ class BrowsingContext final : public JS::Cell {
     // https://html.spec.whatwg.org/multipage/browsers.html#is-popup
     TokenizedFeature::Popup m_is_popup { TokenizedFeature::Popup::No };
 
+    // https://html.spec.whatwg.org/multipage/browsers.html#popup-sandboxing-flag-set
+    SandboxingFlagSet m_popup_sandboxing_flag_set {};
+
     // https://html.spec.whatwg.org/multipage/document-sequences.html#is-auxiliary
     bool m_is_auxiliary { false };
 

Libraries/LibWeb/HTML/Navigable.cpp

@@ -476,13 +476,16 @@ Navigable::ChosenNavigable Navigable::choose_a_navigable(StringView name, Tokeni
                 // 1. Set chosen to the result of creating a new top-level traversable given currentNavigable's active browsing context and targetName.
                 chosen = create_new_traversable->function()(active_browsing_context());
 
-                // FIXME: 2. If sandboxingFlagSet's sandboxed navigation browsing context flag is set,
+                // 2. If sandboxingFlagSet's sandboxed navigation browsing context flag is set,
                 //    then set chosen's active browsing context's one permitted sandboxed navigator to currentNavigable's active browsing context.
+                if (has_flag(sandboxing_flag_set, SandboxingFlagSet::SandboxedNavigation))
+                    chosen->active_browsing_context()->set_the_one_permitted_sandboxed_navigator(active_browsing_context());
             }
 
-            // FIXME: 10. If sandboxingFlagSet's sandbox propagates to auxiliary browsing contexts flag is set,
-            //    then all the flags that are set in sandboxingFlagSet must be set in chosen's active browsing context's popup sandboxing flag set.
-            // Our BrowsingContexts do not have SandboxingFlagSets yet, only documents do
+            // 10. If sandboxingFlagSet's sandbox propagates to auxiliary browsing contexts flag is set,
+            //     then all the flags that are set in sandboxingFlagSet must be set in chosen's active browsing context's popup sandboxing flag set.
+            if (has_flag(sandboxing_flag_set, SandboxingFlagSet::SandboxPropagatesToAuxiliaryBrowsingContexts))
+                chosen->active_browsing_context()->set_popup_sandboxing_flag_set(chosen->active_browsing_context()->popup_sandboxing_flag_set() | sandboxing_flag_set);
         }
 
         // --> If the user agent has been configured such that in this instance t will reuse current