LibWeb: Implement snapshotting source snapshot params per the spec

Author: https://github.com/ADKaster
Commit: 03eae09619
Pull-request: https://github.com/SerenityOS/serenity/pull/20780
Reviewed-by: https://github.com/awesomekling ✅
Reviewed-by: https://github.com/kalenikaliaksandr

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -1315,7 +1315,7 @@ Color Document::visited_link_color() const
 }
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#relevant-settings-object
-HTML::EnvironmentSettingsObject& Document::relevant_settings_object()
+HTML::EnvironmentSettingsObject& Document::relevant_settings_object() const
 {
     // Then, the relevant settings object for a platform object o is the environment settings object of the relevant Realm for o.
     return Bindings::host_defined_environment_settings_object(realm());
@@ -2514,6 +2514,31 @@ HTML::PolicyContainer Document::policy_container() const
     return m_policy_container;
 }
 
+// https://html.spec.whatwg.org/multipage/browsing-the-web.html#snapshotting-source-snapshot-params
+HTML::SourceSnapshotParams Document::snapshot_source_snapshot_params() const
+{
+    // To snapshot source snapshot params given a Document sourceDocument, return a new source snapshot params with
+
+    // has transient activation
+    //    true if sourceDocument's relevant global object has transient activation; otherwise false
+    // sandboxing flags
+    //     sourceDocument's active sandboxing flag set
+    // allows downloading
+    //     false if sourceDocument's active sandboxing flag set has the sandboxed downloads browsing context flag set; otherwise true
+    // fetch client
+    //     sourceDocument's relevant settings object
+    // source policy container
+    //     sourceDocument's policy container
+
+    return HTML::SourceSnapshotParams {
+        .has_transient_activation = verify_cast<HTML::Window>(HTML::relevant_global_object(*this)).has_transient_activation(),
+        .sandboxing_flags = m_active_sandboxing_flag_set,
+        .allows_downloading = (m_active_sandboxing_flag_set.flags & HTML::SandboxingFlagSet::SandboxedDownloads) != HTML::SandboxingFlagSet::SandboxedDownloads,
+        .fetch_client = relevant_settings_object(),
+        .source_policy_container = m_policy_container
+    };
+}
+
 // https://html.spec.whatwg.org/multipage/document-sequences.html#descendant-navigables
 Vector<JS::Handle<HTML::Navigable>> Document::descendant_navigables()
 {

Userland/Libraries/LibWeb/DOM/Document.h

@@ -232,7 +232,7 @@ public:
     DeprecatedString const& source() const { return m_source; }
     void set_source(DeprecatedString source) { m_source = move(source); }
 
-    HTML::EnvironmentSettingsObject& relevant_settings_object();
+    HTML::EnvironmentSettingsObject& relevant_settings_object() const;
 
     void navigate_to_javascript_url(StringView url);
     void evaluate_javascript_url(StringView url);
@@ -530,6 +530,8 @@ public:
 
     u32 unload_counter() const { return m_unload_counter; }
 
+    HTML::SourceSnapshotParams snapshot_source_snapshot_params() const;
+
 protected:
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;

Userland/Libraries/LibWeb/HTML/Navigable.cpp

@@ -814,13 +814,7 @@ WebIDL::ExceptionOr<void> Navigable::navigate(
     ReferrerPolicy::ReferrerPolicy referrer_policy)
 {
     // 1. Let sourceSnapshotParams be the result of snapshotting source snapshot params given sourceDocument.
-    auto source_snapshot_params = SourceSnapshotParams {
+    auto source_snapshot_params = source_document->snapshot_source_snapshot_params();
-        .has_transient_activation = false,
-        .sandboxing_flags = source_document->active_sandboxing_flag_set(),
-        .allows_downloading = true,
-        .fetch_client = source_document->relevant_settings_object(),
-        .source_policy_container = source_document->policy_container()
-    };
 
     // 2. Let initiatorOriginSnapshot be sourceDocument's origin.
     auto initiator_origin_snapshot = source_document->origin();

Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp

@@ -330,15 +330,9 @@ void TraversableNavigable::apply_the_history_step(int step, Optional<SourceSnaps
                 // 3. Let potentiallyTargetSpecificSourceSnapshotParams be sourceSnapshotParams.
                 Optional<SourceSnapshotParams> potentially_target_specific_source_snapshot_params = source_snapshot_params;
 
-                // FIXME: 4. If potentiallyTargetSpecificSourceSnapshotParams is null, then set it to the result of snapshotting source snapshot params given navigable's active document.
+                // 4. If potentiallyTargetSpecificSourceSnapshotParams is null, then set it to the result of snapshotting source snapshot params given navigable's active document.
                 if (!potentially_target_specific_source_snapshot_params.has_value()) {
-                    potentially_target_specific_source_snapshot_params = SourceSnapshotParams {
+                    potentially_target_specific_source_snapshot_params = navigable->active_document()->snapshot_source_snapshot_params();
-                        .has_transient_activation = false,
-                        .sandboxing_flags = navigable->active_document()->active_sandboxing_flag_set(),
-                        .allows_downloading = true,
-                        .fetch_client = navigable->active_document()->relevant_settings_object(),
-                        .source_policy_container = navigable->active_document()->policy_container()
-                    };
                 }
 
                 // 5. Set targetEntry's document state's reload pending to false.