Migration mapping table

This page is a symbol-by-symbol reference for migrating code written against libwpe and WPEBackend-fdo to WPEPlatform. For prose, before/after code, and discussion of the conceptual shifts, see Migrating from libwpe.

The table records what each old symbol does, the closest WPEPlatform equivalent, and — where there isn’t one — why. Three classes of entry:

  • Direct. A symbol that maps to a single WPEPlatform function or class with comparable semantics.
  • Reshape. A symbol whose role is preserved but framed differently (e.g. an opaque C struct + vtable replaced by a GObject + virtual methods).
  • Removed. A symbol whose role is no longer the platform layer’s responsibility (e.g. handled internally by WPE WebKit, or dropped entirely).

libwpe

wpe/view-backend.h

The single biggest concept change. wpe_view_backend and its companion client/handler interfaces are gone; their responsibilities are split across WPEView and WPEToplevel.

libwpe symbol WPEPlatform Kind Notes
struct wpe_view_backend WPEView + WPEToplevel Reshape The single opaque struct becomes two GObject classes. View owns rendering surface; toplevel owns window-level state.
wpe_view_backend_create() wpe_view_new() Reshape View constructor now takes a WPEDisplay argument.
wpe_view_backend_create_with_backend_interface(iface, data) Subclass WPEView / WPEDisplay Reshape The C-vtable extension model is replaced by GObject subclassing.
wpe_view_backend_destroy() g_object_unref() Direct Standard GObject lifecycle.
struct wpe_view_backend_interface WPEView vfuncs + WPEDisplay vfuncs Reshape Vtable split across WPEViewClass and WPEDisplayClass.
wpe_view_backend_set_backend_client(...) View signals (closed, resized, buffers-changed, buffer-rendered, buffer-released, toplevel-state-changed, preferred-buffer-formats-changed) Reshape Per-event signal connections replace a single client struct.
wpe_view_backend_client.set_size WPEView::resized Direct
wpe_view_backend_client.frame_displayed WPEView::buffer-rendered Direct
wpe_view_backend_client.activity_state_changed WPEView::toplevel-state-changed + view focus/visible state Reshape Old wpe_view_activity_state bitfield (visible / focused / in_window) split across WPEToplevelState, wpe_view_get_has_focus(), wpe_view_get_visible().
wpe_view_backend_client.get_accessible wpe_view_get_accessible() / WPEViewAccessible Reshape Now a GObject interface; the accessible is bound by name via wpe_view_accessible_bind().
wpe_view_backend_client.set_device_scale_factor wpe_view_get_scale() / wpe_screen_set_scale() Reshape Scale is now driven by the screen the view is on.
wpe_view_backend_client.target_refresh_rate_changed wpe_screen_set_refresh_rate() Reshape Refresh rate is a screen attribute, not a view attribute.
wpe_view_backend_initialize() Implicit (handled by view/display lifecycle) Removed No separate initialize step.
wpe_view_backend_get_renderer_host_fd() — Removed The renderer-host fd plumbing is gone. WPE WebKit handles UI↔Web-process IPC internally.
wpe_view_backend_set_input_client(...) WPEView::event Reshape Single signal replaces per-input-type callback struct.
wpe_view_backend_input_client.handle_keyboard_event WPEView::event with WPE_EVENT_KEYBOARD_KEY_DOWN/KEYBOARD_KEY_UP Direct
wpe_view_backend_input_client.handle_pointer_event WPEView::event with WPE_EVENT_POINTER_DOWN/UP/MOVE/ENTER/LEAVE Direct
wpe_view_backend_input_client.handle_axis_event WPEView::event with WPE_EVENT_SCROLL Direct
wpe_view_backend_input_client.handle_touch_event WPEView::event with WPE_EVENT_TOUCH_DOWN/UP/MOVE/CANCEL Direct
wpe_view_backend_input_client.handle_pointer_lock_event wpe_view_lock_pointer() / wpe_view_unlock_pointer() Reshape Lock/unlock are direct view operations.
wpe_view_backend_dispatch_set_size(w, h) wpe_view_resized() Direct (Notification form, called by platform implementations.)
wpe_view_backend_dispatch_frame_displayed() wpe_view_buffer_rendered() Direct
wpe_view_activity_state_visible (set via add_activity_state) wpe_view_set_visible() to assert the state; wpe_view_get_mapped() is what WebKit actually reads Reshape “Visible” in libwpe corresponds to WPEPlatform’s mapped state (visible AND not hidden by toplevel state). wpe_view_get_visible alone can be TRUE while get_mapped is FALSE (e.g. minimized). Observe with notify::mapped.
wpe_view_activity_state_focused wpe_view_focus_in() / wpe_view_focus_out() to set; wpe_view_get_has_focus() to read; notify::has-focus to observe Direct
wpe_view_activity_state_in_window A view is “in window” when it has a toplevel attached: wpe_view_set_toplevel() (set), wpe_view_get_toplevel() != NULL (read), notify::toplevel (observe) Reshape By default views are created with a toplevel automatically (see WPE_SETTING_CREATE_VIEWS_WITH_A_TOPLEVEL).
wpe_view_backend_add_activity_state() / _remove_activity_state() / _get_activity_state() bulk APIs The three per-bit accessors above Reshape The bitfield is decomposed; there is no single getter or setter.
wpe_view_activity_state_focused, which WebKit also used to derive ActivityState::WindowIsActive WPE_TOPLEVEL_STATE_ACTIVE from wpe_toplevel_get_state(), observed per-view via WPEView::toplevel-state-changed Reshape libwpe had no active-window state, so WebKit treated a focused view as an active window. WPEPlatform reports window activation separately from view focus, as a WPEToplevelState bit.
wpe_view_backend_dispatch_get_accessible() wpe_view_get_accessible() Direct
wpe_view_backend_dispatch_set_device_scale_factor() Scale is a property of WPEScreen: set with wpe_screen_set_scale() Reshape The scale propagates from the screen to the WPEToplevel (which reads wpe_screen_get_scale()) and then to the WPEView (wpe_view_get_scale() returns the toplevel’s scale). Embedders that previously set the factor on the view backend now set it on the screen instead.
wpe_view_backend_get_target_refresh_rate() / _set_target_refresh_rate() wpe_screen_get_refresh_rate() / wpe_screen_set_refresh_rate() Reshape Refresh rate is now stored on the screen, not the view backend. WebKit reads it from wpe_view_get_screen() → wpe_screen_get_refresh_rate().
wpe_view_backend_dispatch_keyboard_event() wpe_view_event() with a keyboard WPEEvent Reshape Construct event with wpe_event_keyboard_new(), then wpe_view_event().
wpe_view_backend_dispatch_pointer_event() wpe_view_event() with a pointer WPEEvent Reshape wpe_event_pointer_button_new() / wpe_event_pointer_move_new().
wpe_view_backend_dispatch_axis_event() wpe_view_event() with wpe_event_scroll_new() Reshape
wpe_view_backend_dispatch_touch_event() wpe_view_event() with wpe_event_touch_new() Reshape
wpe_view_backend_dispatch_pointer_lock_event() — Removed The pointer-lock event struct is gone; lock/unlock are state operations, not events.
wpe_view_backend_set_fullscreen_client() / _set_fullscreen_handler() / wpe_view_backend_fullscreen_client / wpe_view_backend_fullscreen_handler WPEToplevel state API + WPEView::toplevel-state-changed Reshape Fullscreen is a WPEToplevelState bit; control via wpe_toplevel_fullscreen() / _unfullscreen.
wpe_view_backend_platform_set_fullscreen() wpe_toplevel_fullscreen() / _unfullscreen() Reshape
wpe_view_backend_dispatch_did_enter_fullscreen() / _did_exit_fullscreen() / _request_enter_fullscreen() / _request_exit_fullscreen() WPEView::toplevel-state-changed Reshape Single signal observes all state transitions.
wpe_view_backend_set_pointer_lock_handler() / wpe_view_backend_pointer_lock_handler WPEPlatform.ViewClass.lock_pointer / WPEPlatform.ViewClass.unlock_pointer Reshape Override on a WPEView subclass instead of registering a callback.
wpe_view_backend_request_pointer_lock() / _request_pointer_unlock() wpe_view_lock_pointer() / _unlock_pointer() Direct

wpe/input.h

The event-struct family becomes a single refcounted WPEEvent with typed constructors and accessors.

libwpe symbol WPEPlatform Kind Notes
struct wpe_input_keyboard_event WPEEvent + WPE_EVENT_KEYBOARD_KEY_DOWN/KEYBOARD_KEY_UP Reshape
struct wpe_input_pointer_event WPEEvent + WPE_EVENT_POINTER_DOWN/UP/MOVE/ENTER/LEAVE Reshape Pointer-button and pointer-move are separate constructors in WPEPlatform.
enum wpe_input_pointer_event_type (null/motion/button) WPEEventType Reshape Pointer events are split into more granular event types (down/up/move/enter/leave).
struct wpe_input_pointer_lock_event — Removed Pointer-lock has no event struct; it’s a state transition (see wpe_view_lock_pointer()).
struct wpe_input_axis_event WPEEvent + WPE_EVENT_SCROLL Reshape
struct wpe_input_axis_2d_event WPEEvent + WPE_EVENT_SCROLL (delta_x and delta_y both present) Reshape
enum wpe_input_axis_event_type — Removed Subsumed by WPEEvent type.
struct wpe_input_touch_event WPEEvent + WPE_EVENT_TOUCH_DOWN/UP/MOVE/CANCEL Reshape Multi-touch is now a sequence of single-point events keyed by sequence id.
struct wpe_input_touch_event_raw — Removed No longer needed: each touch event in WPEPlatform represents one touchpoint identified by wpe_event_touch_get_sequence_id().
enum wpe_input_touch_event_type WPEEventType Reshape
enum wpe_input_modifier WPEModifiers Direct keyboard_modifier_control/shift/alt/meta → WPE_MODIFIER_KEYBOARD_CONTROL/SHIFT/ALT/META. Pointer button modifiers preserved. Also adds WPE_MODIFIER_KEYBOARD_CAPS_LOCK.
wpe_key_code_to_unicode(uint32_t) wpe_keyval_to_unicode() Direct Note the rename: keyval, not key_code.
wpe_unicode_to_key_code(uint32_t) wpe_unicode_to_keyval() Direct Same rename.

wpe/input-xkb.h

All wrapped in WPEKeymapXKB, a WPEKeymap subclass.

libwpe symbol WPEPlatform Kind Notes
struct wpe_input_xkb_context WPEKeymapXKB Reshape GObject; per-display rather than a global singleton.
wpe_input_xkb_context_get_default() wpe_display_get_keymap() Reshape Keymap is now obtained from the display.
wpe_input_xkb_context_get_context() — Removed xkb_context is internal.
wpe_input_xkb_context_get_keymap() wpe_keymap_xkb_get_xkb_keymap() Direct
wpe_input_xkb_context_set_keymap() wpe_keymap_xkb_update() Reshape Update from fd/size pair; takes raw keymap descriptor format/fd/size.
wpe_input_xkb_context_get_state() wpe_keymap_xkb_get_xkb_state() Direct
wpe_input_xkb_context_get_compose_table() / _set_compose_table() / _get_compose_state() — Removed xkb_compose handling is internal to the keymap implementation.
wpe_input_xkb_context_get_modifiers(...) wpe_keymap_get_modifiers() Reshape Generic on WPEKeymap, not XKB-specific.
wpe_input_xkb_context_get_key_code(...) wpe_keymap_translate_keyboard_state() Reshape Different signature but covers the same functionality.
wpe_input_xkb_context_get_entries_for_key_code(...) wpe_keymap_get_entries_for_keyval() Reshape Note the direction reversal: WPEPlatform looks up keycodes given a keyval.
struct wpe_input_xkb_keymap_entry (hardware_key_code/layout/level) WPEKeymapEntry (keycode/group/level) Direct Renamed but structurally equivalent.

wpe/keysyms.h

libwpe symbol WPEPlatform Kind Notes
WPE_KEY_* constants WPE_KEY_* constants Direct The constant names are preserved; both files derive from the X11 keysym list and cover the same ~2280 names (a couple of stragglers differ, e.g. WPE_KEY_WindowClearGrab → WPE_KEY_ClearGrab).

wpe/pasteboard.h

Replaced by WPEClipboard, which is more capable (multi-format, GBytes-based, change tracking) than the old singleton.

libwpe symbol WPEPlatform Kind Notes
struct wpe_pasteboard WPEClipboard Reshape GObject, obtained from the display via wpe_display_get_clipboard().
wpe_pasteboard_get_singleton() wpe_display_get_clipboard() Reshape Per-display, not global.
struct wpe_pasteboard_interface WPEClipboard vfuncs (read, changed) Reshape
wpe_pasteboard_get_types() wpe_clipboard_get_formats() Direct Returns formats (MIME types).
wpe_pasteboard_get_string() wpe_clipboard_read_text() Direct
wpe_pasteboard_write() wpe_clipboard_set_content() + WPEClipboardContent builder Reshape Content is built using wpe_clipboard_content_new() + wpe_clipboard_content_set_text() / _set_bytes().
struct wpe_pasteboard_string / _string_vector / _string_pair / _string_map — Removed Replaced by GBytes + string arrays.
wpe_pasteboard_string_initialize() / _string_free() / _string_vector_free() — Removed No equivalent needed: standard GLib types do this work.

wpe/gamepad.h

Maps to WPEGamepad / WPEGamepadManager, both GObject.

libwpe symbol WPEPlatform Kind Notes
struct wpe_gamepad_provider WPEGamepadManager Reshape
struct wpe_gamepad WPEGamepad Reshape
enum wpe_gamepad_axis (4 axes) WPEGamepadAxis Reshape Member names changed: LEFT_STICK_X → LEFT_X, etc.
enum wpe_gamepad_button (17 buttons) WPEGamepadButton Reshape Member names changed: BOTTOM/RIGHT/LEFT/TOP → RIGHT_CLUSTER_BOTTOM/RIGHT/LEFT/TOP, etc.
wpe_gamepad_provider_create() / _destroy() wpe_display_create_gamepad_manager() / g_object_unref() Reshape Manager comes from the display, not a global factory.
wpe_gamepad_provider_set_client() WPEGamepadManager::device-added / device-removed Reshape
wpe_gamepad_provider_start() / _stop() — Removed Lifecycle is implicit: the manager is active from creation until its last reference is dropped. wpe_display_create_gamepad_manager() returns a new reference owned by the caller, and falls back to a libmanette-based manager only when WebKit is built with libmanette.
wpe_gamepad_provider_get_backend() — Removed No equivalent; per-implementation private data is accessed via the GObject subclass directly.
wpe_gamepad_provider_get_view_backend() — Removed Gamepads are not associated with a specific view in WPEPlatform.
wpe_gamepad_provider_dispatch_gamepad_connected() / _disconnected() wpe_gamepad_manager_add_device() / _remove_device() Direct
wpe_gamepad_create() / _destroy() Subclass WPEGamepad in the platform implementation Reshape
wpe_gamepad_set_client() WPEGamepad::button-event / axis-event Reshape
wpe_gamepad_get_id() wpe_gamepad_get_name() Direct Renamed.
wpe_gamepad_dispatch_button_changed() / _analog_button_changed() wpe_gamepad_button_event() Reshape Single API for both press/release events.
wpe_gamepad_dispatch_axis_changed() wpe_gamepad_axis_event() Direct
wpe_gamepad_set_handler() Subclassing Reshape The C-callback handler is replaced by GObject subclassing of both WPEGamepad and WPEGamepadManager.
struct wpe_gamepad_provider_interface WPEGamepadManager subclass (no vfuncs) Reshape The manager has no virtual methods to override; device enumeration drives wpe_gamepad_manager_add_device() / _remove_device.
struct wpe_gamepad_interface WPEGamepad virtual methods (start_input_monitor, stop_input_monitor, has_rumble, rumble) Reshape New WPEPlatform additions: rumble support.

wpe/loader.h

The dlopen-the-.so-you-passed model is replaced by GIO extension points.

libwpe symbol WPEPlatform Kind Notes
wpe_loader_init("libfoo.so") WPE_PLATFORM=<name> env var, or direct instantiation (e.g. wpe_display_wayland_new()) Reshape The “select a backend by .so path” mechanism is gone.
struct wpe_loader_interface (_wpe_loader_interface symbol) GIO extension point "wpe-platform-display" (WPE_DISPLAY_EXTENSION_POINT_NAME) Reshape A module is now a GIO type module that registers itself with this extension point.
wpe_loader_get_loaded_implementation_library_name() — Removed No direct equivalent; introspect the WPEDisplay instance instead (G_OBJECT_TYPE_NAME()).

wpe/process.h (libwpe ≥ 1.14)

libwpe symbol WPEPlatform Kind Notes
enum wpe_process_type — Removed
struct wpe_process_provider — Removed
struct wpe_process_provider_interface — Removed
wpe_process_provider_create() / _destroy() / _register_interface() — Removed
wpe_process_launch() / wpe_process_terminate() — Removed Child-process launch is internal to WPE WebKit again, and platform implementations no longer take part. The exception is Android, where WPEPlatform provides WPEProcessManager (wpe_process_manager_launch() / _terminate()). It is only built and installed for Android.

wpe/renderer-host.h

libwpe symbol WPEPlatform Kind Notes
struct wpe_renderer_host_interface — Removed
wpe_renderer_host_create_client() — Removed UI↔Web-process IPC bootstrapping is internal.

wpe/renderer-backend-egl.h (via wpe/wpe-egl.h)

The EGL renderer-target abstraction is replaced by buffer sharing.

libwpe symbol WPEPlatform Kind Notes
struct wpe_renderer_backend_egl / _target / _offscreen_target — Removed Replaced by WPEBuffer and WPEPlatform.ViewClass.render_buffer.
struct wpe_renderer_backend_egl_interface — Removed
struct wpe_renderer_backend_egl_target_interface — Removed
wpe_renderer_backend_egl_create() / _destroy() — Removed
wpe_renderer_backend_egl_get_native_display() wpe_display_get_egl_display() Reshape Type semantics differ. libwpe returned EGLNativeDisplayType (e.g. an X11 Display* or wl_display*); WPEPlatform returns the already-initialized EGLDisplay. Embedders migrating code that called eglGetDisplay() on the libwpe-returned value should drop that step.
wpe_renderer_backend_egl_get_platform() — Removed Not needed (handled internally).
wpe_renderer_backend_egl_target_* (create, set_client, initialize, get_native_window, resize, frame_will_render, frame_rendered, deinitialize) WPEView + WPEBuffer flow Reshape The whole concept of an EGL target wrapping a native window is gone; instead, the view receives WPEBuffer objects via WPEPlatform.ViewClass.render_buffer.
wpe_renderer_backend_egl_target_dispatch_frame_complete() wpe_view_buffer_rendered() / WPEView::buffer-rendered Reshape
wpe_renderer_backend_egl_offscreen_target_* — Removed

wpe/export.h, wpe/version.h, wpe/libwpe-version.h, wpe/version-deprecated.h

libwpe symbol WPEPlatform Kind Notes
WPE_EXPORT WPE_API (defined in <wpe/WPEDefines.h>) Direct Same role: visibility attribute.
Version macros (WPE_MAJOR_VERSION, WPE_CHECK_VERSION, etc.) WPE_PLATFORM_MAJOR_VERSION, WPE_PLATFORM_MINOR_VERSION, WPE_PLATFORM_MICRO_VERSION, WPE_PLATFORM_CHECK_VERSION (generated WPEVersion.h, pulled in by <wpe/wpe-platform.h>) Reshape Renamed with a PLATFORM infix. Runtime versions are available from wpe_platform_get_major_version() and friends.

WPEBackend-fdo

Most of WPEBackend-fdo’s public surface implemented the “exportable view backend” pattern — where WPE WebKit produced rendered frames as buffers and the embedder displayed them via callbacks. That direction is inverted in WPEPlatform: the embedder (or built-in platform) subclasses WPEView and receives buffers via WPEPlatform.ViewClass.render_buffer. There is no longer a separate fdo-style library between WebKit and the platform.

wpe/fdo.h, wpe/fdo-egl.h (umbrella headers)

WPEBackend-fdo symbol WPEPlatform Kind Notes
<wpe/fdo.h> <wpe/wpe-platform.h> Reshape
<wpe/fdo-egl.h> <wpe/wpe-platform.h> (no EGL-specific umbrella; EGL display via wpe_display_get_egl_display()) Reshape

wpe/initialize-egl.h

WPEBackend-fdo symbol WPEPlatform Kind Notes
wpe_fdo_initialize_for_egl_display(EGLDisplay) — Removed The display manages its own EGL initialization.

wpe/view-backend-exportable.h, wpe/view-backend-exportable-egl.h

WPEBackend-fdo symbol WPEPlatform Kind Notes
struct wpe_view_backend_exportable_fdo WPEView subclass Reshape Subclass and override WPEPlatform.ViewClass.render_buffer instead of registering an exportable backend.
wpe_view_backend_exportable_fdo_create(client, data, w, h) Subclass WPEView, create with wpe_view_new() Reshape
wpe_view_backend_exportable_fdo_destroy() g_object_unref() Direct
wpe_view_backend_exportable_fdo_get_view_backend() — Removed No wrapper object: the WPEView subclass itself is what WebKit renders into.
struct wpe_view_backend_exportable_fdo_client (export_buffer_resource, export_dmabuf_resource, export_shm_buffer) WPEPlatform.ViewClass.render_buffer receiving WPEBuffer subclasses Reshape Single virtual function receives whichever WPEBuffer subclass the system uses.
struct wpe_view_backend_exportable_fdo_dmabuf_resource WPEBufferDMABuf Reshape First-class WPEPlatform type.
struct wpe_view_backend_exportable_fdo_egl_client (export_egl_image, export_fdo_egl_image, export_shm_buffer) WPEPlatform.ViewClass.render_buffer Reshape EGLImage-vs-DMA-BUF distinction is handled by the buffer subclass.
wpe_view_backend_exportable_fdo_egl_create(...) Subclass + wpe_view_new() Reshape
wpe_view_backend_exportable_fdo_dispatch_frame_complete() wpe_view_buffer_rendered() Reshape
wpe_view_backend_exportable_fdo_dispatch_release_buffer() wpe_view_buffer_released() Reshape
wpe_view_backend_exportable_fdo_dispatch_release_shm_exported_buffer() wpe_view_buffer_released() Reshape
wpe_view_backend_exportable_fdo_egl_dispatch_release_image() wpe_view_buffer_released() Reshape
wpe_view_backend_exportable_fdo_egl_dispatch_release_exported_image() wpe_view_buffer_released() Reshape

wpe/exported-image-egl.h

WPEBackend-fdo symbol WPEPlatform Kind Notes
struct wpe_fdo_egl_exported_image WPEBufferDMABuf Reshape The “image with width/height” abstraction is folded into the buffer class.
wpe_fdo_egl_exported_image_get_width() / _get_height() wpe_buffer_get_width() / get_height() Direct
wpe_fdo_egl_exported_image_get_egl_image() wpe_buffer_import_to_egl_image() Reshape

wpe/exported-buffer-shm.h

WPEBackend-fdo symbol WPEPlatform Kind Notes
struct wpe_fdo_shm_exported_buffer WPEBufferSHM Reshape
wpe_fdo_shm_exported_buffer_get_resource() — Removed Wayland wl_resource is no longer the contract; pixel data is via wpe_buffer_shm_get_data().
wpe_fdo_shm_exported_buffer_get_shm_buffer() — Removed Same as above.

wpe/unstable/*

WPEBackend-fdo symbol WPEPlatform Kind Notes
DMA-BUF pool (wpe_view_backend_dmabuf_pool_fdo, wpe_dmabuf_pool_entry) — Removed Not part of the WPEPlatform public surface.
EGLStream variant (wpe_view_backend_exportable_fdo_eglstream*, wpe_fdo_initialize_eglstream()) — Removed EGLStream-specific path is gone.
Explicit SHM/DMA-BUF initialize calls (wpe_fdo_initialize_dmabuf, _initialize_shm) — Removed The display picks its buffer types automatically.

wpe/extensions/*

These two extensions have no counterpart in the WPEPlatform public API:

  • wpe_audio_source / wpe_audio_receiver (<wpe/extensions/audio.h>) — an external-audio sink: WebKit passed packets of raw PCM frames, each in its own memfd, to the embedder for it to render, instead of driving PulseAudio/ALSA. WebKit dropped support for this protocol in 2.46 (commit 281281@main). No WPEPlatform equivalent; audio uses WebKit’s normal output path.
  • wpe_video_plane_display_dmabuf_source / _receiver (<wpe/extensions/video-plane-display-dmabuf.h>) — zero-copy display of decoded video frames on a hardware overlay plane (Broadcom-class SoCs). A WPEPlatform equivalent is in progress — a Broadcom Nexus proof-of-concept has been prototyped — but the public API had not landed when this page was written.

What's new in WPEPlatform with no libwpe / fdo predecessor

The following are first-class WPEPlatform APIs that did not exist in the old stack at all: