LibWebView+WebContent: Add IPC to run the fragment serialization steps

Userland/Libraries/LibWebView/OutOfProcessWebView.cpp

@@ -447,6 +447,11 @@ void OutOfProcessWebView::get_source()
     client().async_get_source();
 }
 
+String OutOfProcessWebView::serialize_source()
+{
+    return client().serialize_source();
+}
+
 void OutOfProcessWebView::inspect_dom_tree()
 {
     client().async_inspect_dom_tree();

Userland/Libraries/LibWebView/OutOfProcessWebView.h

@@ -37,6 +37,7 @@ public:
 
     void debug_request(String const& request, String const& argument = {});
     void get_source();
+    String serialize_source();
 
     void inspect_dom_tree();
     struct DOMNodeProperties {

Userland/Services/WebContent/ConnectionFromClient.cpp

@@ -257,6 +257,20 @@ void ConnectionFromClient::get_source()
     }
 }
 
+Messages::WebContentServer::SerializeSourceResponse ConnectionFromClient::serialize_source()
+{
+    if (auto* doc = page().top_level_browsing_context().active_document()) {
+        auto result = doc->serialize_fragment(Web::DOMParsing::RequireWellFormed::Yes);
+        if (!result.is_error())
+            return { result.release_value() };
+
+        auto source = MUST(doc->serialize_fragment(Web::DOMParsing::RequireWellFormed::No));
+        return { move(source) };
+    }
+
+    return { {} };
+}
+
 void ConnectionFromClient::inspect_dom_tree()
 {
     if (auto* doc = page().top_level_browsing_context().active_document()) {

Userland/Services/WebContent/ConnectionFromClient.h

@@ -62,6 +62,7 @@ private:
     virtual void remove_backing_store(i32) override;
     virtual void debug_request(String const&, String const&) override;
     virtual void get_source() override;
+    virtual Messages::WebContentServer::SerializeSourceResponse serialize_source() override;
     virtual void inspect_dom_tree() override;
     virtual Messages::WebContentServer::InspectDomNodeResponse inspect_dom_node(i32 node_id, Optional<Web::CSS::Selector::PseudoElement> const& pseudo_element) override;
     virtual Messages::WebContentServer::GetHoveredNodeIdResponse get_hovered_node_id() override;

Userland/Services/WebContent/WebContentServer.ipc

@@ -32,6 +32,7 @@ endpoint WebContentServer
 
     debug_request(String request, String argument) =|
     get_source() =|
+    serialize_source() => (String source)
     inspect_dom_tree() =|
     inspect_dom_node(i32 node_id, Optional<Web::CSS::Selector::PseudoElement> pseudo_element) => (bool has_style, String specified_style, String computed_style, String custom_properties, String node_box_sizing)
     get_hovered_node_id() => (i32 node_id)