LibWebView+WebContent: Begin handling open user dialogs for WebDriver

The way in which dialogs should be handled is configurable by the driver
capabilities object, which we don't support yet. So this implements just
the default mode to dismiss the dialog and return an error if there is
one open.

In the OOPWV, this means we need to refer to the dialog after it has
been open, so we now hold a pointer to whatever dialog is open.

Userland/Libraries/LibWebView/OutOfProcessWebView.cpp

@@ -10,6 +10,7 @@
 #include <LibFileSystemAccessClient/Client.h>
 #include <LibGUI/Application.h>
 #include <LibGUI/Desktop.h>
+#include <LibGUI/Dialog.h>
 #include <LibGUI/InputBox.h>
 #include <LibGUI/MessageBox.h>
 #include <LibGUI/Painter.h>
@@ -347,23 +348,46 @@ void OutOfProcessWebView::notify_server_did_request_image_context_menu(Badge<Web
 
 void OutOfProcessWebView::notify_server_did_request_alert(Badge<WebContentClient>, String const& message)
 {
-    GUI::MessageBox::show(window(), message, "Alert"sv, GUI::MessageBox::Type::Information);
+    m_dialog = GUI::MessageBox::construct(window(), message, "Alert"sv, GUI::MessageBox::Type::Information, GUI::MessageBox::InputType::OK);
+    m_dialog->set_icon(window()->icon());
+    m_dialog->exec();
+
     client().async_alert_closed();
+    m_dialog = nullptr;
 }
 
 void OutOfProcessWebView::notify_server_did_request_confirm(Badge<WebContentClient>, String const& message)
 {
-    auto confirm_result = GUI::MessageBox::show(window(), message, "Confirm"sv, GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::OKCancel);
+    m_dialog = GUI::MessageBox::construct(window(), message, "Confirm"sv, GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::OKCancel);
-    client().async_confirm_closed(confirm_result == GUI::Dialog::ExecResult::OK);
+    m_dialog->set_icon(window()->icon());
+
+    client().async_confirm_closed(m_dialog->exec() == GUI::Dialog::ExecResult::OK);
+    m_dialog = nullptr;
 }
 
 void OutOfProcessWebView::notify_server_did_request_prompt(Badge<WebContentClient>, String const& message, String const& default_)
 {
-    String response { default_ };
+    m_dialog = GUI::InputBox::construct(window(), default_, message, "Prompt"sv, StringView {}, GUI::InputType::Text);
-    if (GUI::InputBox::show(window(), response, message, "Prompt"sv) == GUI::InputBox::ExecResult::OK)
+    m_dialog->set_icon(window()->icon());
-        client().async_prompt_closed(move(response));
+
+    if (m_dialog->exec() == GUI::InputBox::ExecResult::OK)
+        client().async_prompt_closed(static_cast<GUI::InputBox&>(*m_dialog).text_value());
     else
         client().async_prompt_closed({});
+
+    m_dialog = nullptr;
+}
+
+void OutOfProcessWebView::notify_server_did_request_accept_dialog(Badge<WebContentClient>)
+{
+    if (m_dialog)
+        m_dialog->done(GUI::Dialog::ExecResult::OK);
+}
+
+void OutOfProcessWebView::notify_server_did_request_dismiss_dialog(Badge<WebContentClient>)
+{
+    if (m_dialog)
+        m_dialog->done(GUI::Dialog::ExecResult::Cancel);
 }
 
 void OutOfProcessWebView::notify_server_did_get_source(const AK::URL& url, String const& source)

Userland/Libraries/LibWebView/OutOfProcessWebView.h

@@ -158,6 +158,8 @@ private:
     virtual void notify_server_did_request_alert(Badge<WebContentClient>, String const& message) override;
     virtual void notify_server_did_request_confirm(Badge<WebContentClient>, String const& message) override;
     virtual void notify_server_did_request_prompt(Badge<WebContentClient>, String const& message, String const& default_) override;
+    virtual void notify_server_did_request_accept_dialog(Badge<WebContentClient>) override;
+    virtual void notify_server_did_request_dismiss_dialog(Badge<WebContentClient>) override;
     virtual void notify_server_did_get_source(const AK::URL& url, String const& source) override;
     virtual void notify_server_did_get_dom_tree(String const& dom_tree) override;
     virtual void notify_server_did_get_dom_node_properties(i32 node_id, String const& specified_style, String const& computed_style, String const& custom_properties, String const& node_box_sizing) override;
@@ -204,6 +206,7 @@ private:
     } m_client_state;
 
     RefPtr<Gfx::Bitmap> m_backup_bitmap;
+    RefPtr<GUI::Dialog> m_dialog;
 };
 
 }

Userland/Libraries/LibWebView/ViewImplementation.h

@@ -44,6 +44,8 @@ public:
     virtual void notify_server_did_request_alert(Badge<WebContentClient>, String const& message) = 0;
     virtual void notify_server_did_request_confirm(Badge<WebContentClient>, String const& message) = 0;
     virtual void notify_server_did_request_prompt(Badge<WebContentClient>, String const& message, String const& default_) = 0;
+    virtual void notify_server_did_request_accept_dialog(Badge<WebContentClient>) = 0;
+    virtual void notify_server_did_request_dismiss_dialog(Badge<WebContentClient>) = 0;
     virtual void notify_server_did_get_source(const AK::URL& url, String const& source) = 0;
     virtual void notify_server_did_get_dom_tree(String const& dom_tree) = 0;
     virtual void notify_server_did_get_dom_node_properties(i32 node_id, String const& specified_style, String const& computed_style, String const& custom_properties, String const& node_box_sizing) = 0;

Userland/Libraries/LibWebView/WebContentClient.cpp

@@ -191,6 +191,16 @@ void WebContentClient::did_request_prompt(String const& message, String const& d
     m_view.notify_server_did_request_prompt({}, message, default_);
 }
 
+void WebContentClient::did_request_accept_dialog()
+{
+    m_view.notify_server_did_request_accept_dialog({});
+}
+
+void WebContentClient::did_request_dismiss_dialog()
+{
+    m_view.notify_server_did_request_dismiss_dialog({});
+}
+
 void WebContentClient::did_change_favicon(Gfx::ShareableBitmap const& favicon)
 {
     if (!favicon.is_valid()) {

Userland/Libraries/LibWebView/WebContentClient.h

@@ -60,6 +60,8 @@ private:
     virtual void did_request_alert(String const&) override;
     virtual void did_request_confirm(String const&) override;
     virtual void did_request_prompt(String const&, String const&) override;
+    virtual void did_request_accept_dialog() override;
+    virtual void did_request_dismiss_dialog() override;
     virtual Messages::WebContentClient::DidRequestAllCookiesResponse did_request_all_cookies(AK::URL const&) override;
     virtual Messages::WebContentClient::DidRequestNamedCookieResponse did_request_named_cookie(AK::URL const&, String const&) override;
     virtual Messages::WebContentClient::DidRequestCookieResponse did_request_cookie(AK::URL const&, u8) override;

Userland/Services/WebContent/PageHost.cpp

@@ -305,6 +305,21 @@ void PageHost::prompt_closed(String response)
     }
 }
 
+void PageHost::dismiss_dialog()
+{
+    switch (m_pending_dialog) {
+    case PendingDialog::None:
+        break;
+    case PendingDialog::Alert:
+        m_client.async_did_request_accept_dialog();
+        break;
+    case PendingDialog::Confirm:
+    case PendingDialog::Prompt:
+        m_client.async_did_request_dismiss_dialog();
+        break;
+    }
+}
+
 void PageHost::page_did_change_favicon(Gfx::Bitmap const& favicon)
 {
     m_client.async_did_change_favicon(favicon.to_shareable_bitmap());

Userland/Services/WebContent/PageHost.h

@@ -55,6 +55,7 @@ public:
     };
     bool has_pending_dialog() const { return m_pending_dialog != PendingDialog::None; }
     PendingDialog pending_dialog() const { return m_pending_dialog; }
+    void dismiss_dialog();
 
 private:
     // ^PageClient

Userland/Services/WebContent/WebContentClient.ipc

@@ -32,6 +32,8 @@ endpoint WebContentClient
     did_request_alert(String message) =|
     did_request_confirm(String message) =|
     did_request_prompt(String message, String default_) =|
+    did_request_accept_dialog() =|
+    did_request_dismiss_dialog() =|
     did_get_source(URL url, String source) =|
     did_get_dom_tree(String dom_tree) =|
     did_get_dom_node_properties(i32 node_id, String specified_style, String computed_style, String custom_properties, String node_box_sizing_json) =|

Userland/Services/WebContent/WebDriverConnection.cpp

@@ -322,7 +322,10 @@ Messages::WebDriverClient::NavigateToResponse WebDriverConnection::navigate_to(J
     URL url(payload.as_object().get_ptr("url"sv)->as_string());
 
     // FIXME: 3. If url is not an absolute URL or is not an absolute URL with fragment or not a local scheme, return error with error code invalid argument.
-    // FIXME: 4. Handle any user prompts and return its value if it is an error.
+
+    // 4. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
+
     // FIXME: 5. Let current URL be the current top-level browsing context’s active document’s URL.
     // FIXME: 6. If current URL and url do not have the same absolute URL:
     // FIXME:     a. If timer has not been started, start a timer. If this algorithm has not completed before timer reaches the session’s session page load timeout in milliseconds, return an error with error code timeout.
@@ -348,7 +351,8 @@ Messages::WebDriverClient::GetCurrentUrlResponse WebDriverConnection::get_curren
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let url be the serialization of the current top-level browsing context’s active document’s document URL.
     auto url = m_page_host.page().top_level_browsing_context().active_document()->url().to_string();
@@ -363,7 +367,8 @@ Messages::WebDriverClient::BackResponse WebDriverConnection::back()
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Traverse the history by a delta –1 for the current browsing context.
     m_web_content_client.async_did_request_navigate_back();
@@ -381,7 +386,8 @@ Messages::WebDriverClient::ForwardResponse WebDriverConnection::forward()
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Traverse the history by a delta 1 for the current browsing context.
     m_web_content_client.async_did_request_navigate_forward();
@@ -399,7 +405,8 @@ Messages::WebDriverClient::RefreshResponse WebDriverConnection::refresh()
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Initiate an overridden reload of the current top-level browsing context’s active document.
     m_web_content_client.async_did_request_refresh();
@@ -419,7 +426,8 @@ Messages::WebDriverClient::GetTitleResponse WebDriverConnection::get_title()
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let title be the initial value of the title IDL attribute of the current top-level browsing context's active document.
     auto title = m_page_host.page().top_level_browsing_context().active_document()->title();
@@ -444,7 +452,8 @@ Messages::WebDriverClient::CloseWindowResponse WebDriverConnection::close_window
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Close the current top-level browsing context.
     m_page_host.page().top_level_browsing_context().close();
@@ -478,7 +487,8 @@ Messages::WebDriverClient::GetWindowRectResponse WebDriverConnection::get_window
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Return success with data set to the WindowRect object for the current top-level browsing context.
     return serialize_rect(compute_window_rect(m_page_host.page()));
@@ -533,7 +543,9 @@ Messages::WebDriverClient::SetWindowRectResponse WebDriverConnection::set_window
     // 8. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 9. Handle any user prompts and return its value if it is an error.
+    // 9. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
+
     // FIXME: 10. Fully exit fullscreen.
 
     // 11. Restore the window.
@@ -572,7 +584,9 @@ Messages::WebDriverClient::MaximizeWindowResponse WebDriverConnection::maximize_
     // 2. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 3. Handle any user prompts and return its value if it is an error.
+    // 3. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
+
     // FIXME: 4. Fully exit fullscreen.
 
     // 5. Restore the window.
@@ -593,7 +607,9 @@ Messages::WebDriverClient::MinimizeWindowResponse WebDriverConnection::minimize_
     // 2. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 3. Handle any user prompts and return its value if it is an error.
+    // 3. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
+
     // FIXME: 4. Fully exit fullscreen.
 
     // 5. Iconify the window.
@@ -611,7 +627,8 @@ Messages::WebDriverClient::FullscreenWindowResponse WebDriverConnection::fullscr
     // 2. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 3. Handle any user prompts and return its value if it is an error.
+    // 3. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 4. Restore the window.
     restore_the_window();
@@ -643,7 +660,8 @@ Messages::WebDriverClient::FindElementResponse WebDriverConnection::find_element
     // 5. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 6. Handle any user prompts and return its value if it is an error.
+    // 6. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 7. Let start node be the current browsing context’s document element.
     auto* start_node = m_page_host.page().top_level_browsing_context().active_document();
@@ -680,7 +698,8 @@ Messages::WebDriverClient::FindElementsResponse WebDriverConnection::find_elemen
     // 5. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 6. Handle any user prompts and return its value if it is an error.
+    // 6. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 7. Let start node be the current browsing context’s document element.
     auto* start_node = m_page_host.page().top_level_browsing_context().active_document();
@@ -711,7 +730,8 @@ Messages::WebDriverClient::FindElementFromElementResponse WebDriverConnection::f
     // 5. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 6. Handle any user prompts and return its value if it is an error.
+    // 6. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 7. Let start node be the result of trying to get a known connected element with url variable element id.
     auto* start_node = TRY(get_known_connected_element(element_id));
@@ -744,7 +764,8 @@ Messages::WebDriverClient::FindElementsFromElementResponse WebDriverConnection::
     // 5. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 6. Handle any user prompts and return its value if it is an error.
+    // 6. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 7. Let start node be the result of trying to get a known connected element with url variable element id.
     auto* start_node = TRY(get_known_connected_element(element_id));
@@ -771,7 +792,8 @@ Messages::WebDriverClient::FindElementFromShadowRootResponse WebDriverConnection
     // 5. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 6. Handle any user prompts and return its value if it is an error.
+    // 6. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 7. Let start node be the result of trying to get a known shadow root with url variable shadow id.
     auto* start_node = TRY(get_known_shadow_root(shadow_id));
@@ -804,7 +826,8 @@ Messages::WebDriverClient::FindElementsFromShadowRootResponse WebDriverConnectio
     // 5. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 6. Handle any user prompts and return its value if it is an error.
+    // 6. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 7. Let start node be the result of trying to get a known shadow root with url variable shadow id.
     auto* start_node = TRY(get_known_shadow_root(shadow_id));
@@ -819,7 +842,8 @@ Messages::WebDriverClient::GetActiveElementResponse WebDriverConnection::get_act
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let active element be the active element of the current browsing context’s document element.
     auto* active_element = m_page_host.page().top_level_browsing_context().active_document()->active_element();
@@ -838,7 +862,8 @@ Messages::WebDriverClient::GetElementShadowRootResponse WebDriverConnection::get
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -863,7 +888,8 @@ Messages::WebDriverClient::IsElementSelectedResponse WebDriverConnection::is_ele
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -898,7 +924,8 @@ Messages::WebDriverClient::GetElementAttributeResponse WebDriverConnection::get_
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -930,7 +957,8 @@ Messages::WebDriverClient::GetElementPropertyResponse WebDriverConnection::get_e
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -960,7 +988,8 @@ Messages::WebDriverClient::GetElementCssValueResponse WebDriverConnection::get_e
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -992,7 +1021,8 @@ Messages::WebDriverClient::GetElementTextResponse WebDriverConnection::get_eleme
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -1010,7 +1040,8 @@ Messages::WebDriverClient::GetElementTagNameResponse WebDriverConnection::get_el
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -1028,7 +1059,8 @@ Messages::WebDriverClient::GetElementRectResponse WebDriverConnection::get_eleme
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -1058,7 +1090,8 @@ Messages::WebDriverClient::IsElementEnabledResponse WebDriverConnection::is_elem
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -1083,7 +1116,8 @@ Messages::WebDriverClient::GetSourceResponse WebDriverConnection::get_source()
     // 1. If the current browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     auto* document = m_page_host.page().top_level_browsing_context().active_document();
     Optional<String> source;
@@ -1340,7 +1374,8 @@ Messages::WebDriverClient::TakeElementScreenshotResponse WebDriverConnection::ta
     // 1. If the current top-level browsing context is no longer open, return error with error code no such window.
     TRY(ensure_open_top_level_browsing_context());
 
-    // FIXME: 2. Handle any user prompts and return its value if it is an error.
+    // 2. Handle any user prompts and return its value if it is an error.
+    TRY(handle_any_user_prompts());
 
     // 3. Let element be the result of trying to get a known connected element with url variable element id.
     auto* element = TRY(get_known_connected_element(element_id));
@@ -1375,6 +1410,40 @@ ErrorOr<void, Web::WebDriver::Error> WebDriverConnection::ensure_open_top_level_
     return {};
 }
 
+// https://w3c.github.io/webdriver/#dfn-handle-any-user-prompts
+ErrorOr<void, Web::WebDriver::Error> WebDriverConnection::handle_any_user_prompts()
+{
+    // 1. If there is no current user prompt, abort these steps and return success.
+    if (!m_page_host.has_pending_dialog())
+        return {};
+
+    // 2. Perform the following substeps based on the current session’s user prompt handler:
+
+    // FIXME: The user prompt handler is a capability-level configuration, which we have no support
+    //        for yet. It defaults to "dismiss and notify", so that is all that is handled here.
+
+    // -> dismiss state
+    //    Dismiss the current user prompt.
+    // -> accept state
+    //    Accept the current user prompt.
+    // -> dismiss and notify state
+    if (true) {
+        // Dismiss the current user prompt.
+        m_page_host.dismiss_dialog();
+
+        // Return an annotated unexpected alert open error.
+        return Web::WebDriver::Error::from_code(Web::WebDriver::ErrorCode::UnexpectedAlertOpen, "A user dialog is open"sv);
+    }
+    // -> accept and notify state
+    //    Accept the current user prompt.
+    //    Return an annotated unexpected alert open error.
+    // -> ignore state
+    //     Return an annotated unexpected alert open error.
+
+    // 3. Return success.
+    return {};
+}
+
 // https://w3c.github.io/webdriver/#dfn-restore-the-window
 void WebDriverConnection::restore_the_window()
 {

Userland/Services/WebContent/WebDriverConnection.h

@@ -82,6 +82,7 @@ private:
     virtual Messages::WebDriverClient::TakeElementScreenshotResponse take_element_screenshot(String const& element_id) override;
 
     ErrorOr<void, Web::WebDriver::Error> ensure_open_top_level_browsing_context();
+    ErrorOr<void, Web::WebDriver::Error> handle_any_user_prompts();
     void restore_the_window();
     Gfx::IntRect maximize_the_window();
     Gfx::IntRect iconify_the_window();