The Storage panel expects storesUpdate messages after watched storage
changes. Summarize committed IndexedDB mutation logs into DevTools paths
and forward them through WebContent so Firefox can refresh database,
object-store, and record rows without polling.
Firefox's behaviour is less than ideal here. A lot of things don't
update automatically even inspecting a page in Firefox. Some
things (like new databases) won't show up until you fully refresh the
page. So that makes it a bit hard to know that we're doing things
correctly. As far as I can tell, we are at least behaving as well as
Firefox requires.
We do have one workaround: Firefox doesn't display record updates
without a manual refresh, and in fact any change messages for them show
up as rows in the host's database table. So for now, we filter them out
to avoid visual weirdness in the inspector.
Firefox asks the storage watcher for an indexed-db resource before it
shows IndexedDB entries in the Storage panel. Add an IndexedDB actor and
serialize the live LibWeb database registry on demand, so WebContent can
return the host tree and table rows without duplicating database state.
Use the LibWeb inspection helpers to read IndexedDB internals, and keep
the Firefox protocol shape in LibDevTools. WebContent only forwards the
serialized response over the existing DevTools IPC path.
The autoplay setting was binary and its default blocked all media,
including muted video, leaving sites that rely on muted autoplay
visibly broken. Replace it with a tri-state user-agent autoplay
policy (allow audio and video, block audio, or block audio and video)
defaulting to allowing only inaudible media to autoplay.
This is enforced through the media element's "allowed to play" check,
so unmuting a muted autoplay or calling `play()` cannot slip audio
past the policy; audible playback is permitted once the document has
been activated by the user. The policy lives in a dedicated
AutoplaySettings consulted from HTMLMediaElement instead of the
Permissions Policy "allowed to use feature" check it was previously
conflated with.
Show native history menus when users right-click or long-press
the back and forward toolbar buttons. Populate entries from the
UI-process session history mirror, using saved history titles and
favicons when available and falling back to the URL and globe icon
otherwise.
Share the Qt base64 PNG icon helper so bookmark menus and navigation
history menus render stored favicons consistently.
Keep UI process session history authoritative across overlapping
fallback loads and traversals. WebContent can finish a superseded
history load with a live document matching the UI seed URL while its
local step, document state id, and Navigation API keys still describe
a temporary partial list.
Reconstruct the current entry around the UI-owned list in that case.
This avoids making the UI process adopt WebContent's incomplete
snapshot.
Track UI-started fallback loads by URL so unrelated navigations cannot
consume the pending seed state. Resolve deferred WebDriver completions
through the view registry so callbacks queued before a process swap do
not touch a destroyed view.
Add WebDriver coverage that waits for explicit UI/WebContent history
convergence after the relevant document events. The waits poll
observable history state instead of depending on timing.
Apply pinch zoom deltas to the compositor's visual viewport transform
so the currently presented display list can respond without waiting for
the WebContent main thread. Keep the normal WebContent pinch event path
so the real VisualViewport state and DOM-visible events catch up after.
Only take the compositor path when async scrolling is enabled and there
are no blocking wheel listeners, since pinch zoom dispatches a synthetic
wheel event that script may cancel. Coalesce queued pinch events in
WebContent so main-thread catch-up can adopt multiple gesture deltas
together.
Use the compositor visual viewport transform for wheel hit testing and
consume wheel deltas as visual viewport pan while zoomed. Scale the
handoff to layout viewport scrolling by the inverse visual viewport
scale, so touchpad momentum does not jump when the visual viewport hits
an edge.
Same-document navigations now commit synchronously in WebContent, while
the UI process mirror learns about them over asynchronous IPC. A stale
UI seed could be accepted back into a live non-initial document and
overwrite its latest entry, making queued traversals target unreachable
entries.
Share descriptor comparison helpers between LibWeb and LibWebView.
Reject stale top-level seeds against the active document latest entry,
and let the UI process adopt WebContent current snapshots when a seed is
rejected. Test-only session history dumps now first send WebContent
current state synchronously, so dumps observe the converged state.
Allow post-load UI seeds to carry UI-owned nested histories that the
freshly loaded top-level document has not reconstructed yet. Add unit
coverage for matching those seeds while still checking top-level state.
Complete pending WebDriver navigation waits when WebContent confirms
that a same-document history traversal step was applied. These
traversals do not always produce a load event, and waiting only for a
later session history snapshot could let the WebDriver command return
before the UI had observed the applied step.
This keeps the WebDriver session history test from racing into later
commands while a previous same-document traversal is still settling.
Use the LibWebView history mirror to preserve traversable session
history across WebContent process swaps. WebContent reports snapshots to
the UI process, and new renderers can be seeded from the mirror.
Browser back and forward now resolve through the UI-owned used history
steps. WebContent still runs the spec traversal path when the current
renderer has enough matching state to do so.
Handle canceled and no-op UI navigations without leaving speculative
history entries or pending WebDriver waits behind. Preserve traversal
precheck state across synchronous IPC shutdown, and avoid overwriting a
restored target entry's persisted scroll state before the document has
adopted that entry.
Firefox sends the same storage actor mutation requests for Web Storage
that it uses for cookies. Handle addItem, editItem, removeItem, and
removeAll for localStorage and sessionStorage actors.
Apply the changes through the browser-process storage jar and emit the
matching store update packets so the Storage panel stays current after a
DevTools-initiated edit.
Firefox keeps the Storage panel current by sending store update packets
when localStorage or sessionStorage changes. Forward successful Web
Storage mutations to the storage actors and emit the matching update or
clear packet.
Use listener IDs for storage updates so the local and session storage
actors can subscribe independently.
Firefox exposes localStorage and sessionStorage through the same
storage actor protocol used by cookies. Add matching resources for the
current tab so the Storage panel can list key/value pairs.
Read the values through WebContent rather than directly from the
browser process. Session storage lives in LibWeb, and using the same
path for both stores keeps the actor independent of the backing store.
Firefox keeps the Storage table current through storesUpdate messages
from the storage actor. Forward browser cookie change notifications to
the cookies actor and classify visible rows against a fresh cookie
snapshot.
The existing cookie-change notifications report cookies that are
relevant to a specific page, whereas DevTools wants all cookies
relevant for a host, so we end up having to provide two different sets
of cookies to `notify_cookies_changed()`.
Extend the existing DOM node inspection request with an options payload
and carry it through the browser process, WebView, IPC, and WebContent.
This lets later DevTools requests forward Firefox's top-level flags
without changing any inspected-node behavior yet.
Enable -Wexit-time-destructors for all in-tree library targets and
update process-lifetime library statics so they no longer register
exit-time destructors. Long-lived caches, lookup tables, singleton
registries, and generated constants now use NeverDestroyed or leaked
references where the data is intended to live until process exit.
Update LibWeb, LibLine, and the binding generators so regenerated
sources follow the same rule instead of reintroducing destructed
statics.
Platform wheel deltas describe movement in the view, not in page CSS
pixels. Convert them by page zoom before dispatch so physical scrolling
covers a smaller page area when zoomed in.
Do this before the UI-side async scrolling shortcut so compositor
scrolling and main-thread fallback scrolling use the same delta. Also
avoid applying the Qt device pixel ratio while converting angle-only
wheel input, since LibWeb later handles device-pixel scaling itself.
LibWebView owns the active page connection and bridges the DevTools
delegate to WebContent. Track picker state there, translate UI hover,
preview, pick, and cancel requests into hit-test IPC, and forward the
resulting node ids back through the DevTools callback.
Keeping the request bookkeeping in LibWebView also lets the platform UI
frontends share the same picker behavior.
Keep the outgoing front bitmap as the backup image before replacing the
WebContent process for cross-site navigation. This lets the view keep
painting the old page until the new process presents its first frame,
rather than falling back to a flat background during loading.
Remember the preferred color scheme selected through the debug menu when
choosing the web view fallback background. Keep using an explicit forced
scheme even if the platform theme changes underneath it.
Seed the page background fallback from the platform color scheme before
WebContent has painted. Update the same fallback when the platform theme
changes, and when the preferred color scheme is forced through the debug
menu, so unpainted web view areas use the matching Canvas color.
Add IPC structures and requests for inspecting grid layout data from
WebContent.
WebView forwards the async replies to LibDevTools and exposes the grid
highlighter hooks used by the protocol layer.
Parse Firefox grid highlighter options in WebContent and store them with
the active grid highlight.
Send hidden and visible system visibility updates from explicit tab
switch paths instead of relying only on widget show and hide events. Tab
containers can keep inactive web views mapped, which leaves documents
visible from WebContent's perspective and lets animated images keep
running in background tabs.
Use AppKit window occlusion state rather than the app-wide active tab.
That keeps still-visible background windows in the visible document
state. Avoid resending duplicate visibility updates from
ViewImplementation so existing widget visibility notifications remain
harmless.
Track whether WebContent still needs a beforeunload check and let the
frontends immediately remove a tab or window when no prompt can be
shown. WebContent still receives the close request so pagehide, unload,
and cleanup steps can run.
When the visible view is removed immediately, keep detached ownership of
the WebContent page until it reports that the top-level traversable
closed. If no acknowledgement arrives, release detached ownership and
ask ProcessManager to shut down the unused WebContent process.
Tell the compositor that viewport updates from handle_resize are part of
a resize operation. This keeps the compositor backing store manager on
its padded live-resize path instead of forcing an exact-size backing
store allocation for every browser window resize tick.
Remove the command-line option that allowed Browser to start
WebContent with the in-process compositor thread instead of the
Compositor helper process. The compositor process is now the default
path, so the opt-out flag and the matching WebContent selector only kept
the old thread mode reachable.
With that option gone, simplify Browser and WebContent startup to wire
each WebContent process to the Compositor process directly. The old
local Browser-to-WebContent compositor IPC setup and its fallback input
and ready-to-paint branches are no longer needed.
Notify the UI process with the solid canvas background color recorded
for the top-level document. This is the Canvas system color with the
effective document background composited over it, matching the color
used before normal painting.
Store that color on the view and use it when AppKit, Qt, and Gtk need
to fill areas exposed while an older bitmap is still on screen during a
window resize.
The browser previously treated the out-of-process Compositor as fatal.
Restart the shared Compositor from the browser process, reconnect
process-backed WebContent clients, recreate compositor contexts, restore
viewport state, and ask WebContent to repaint and republish canvas and
media resources. WebContent now marks its compositor connection lost,
returns conservative values for synchronous compositor queries while
reconnecting, and drops outgoing updates until the replacement transport
arrives.
Synchronous input queries through the compositor control connection now
use fallible IPC. If the Compositor exits after the open check or before
the sync reply arrives, scroll and mouse handling report that the
Compositor did not handle the event and let the normal WebContent
fallback run.
Mouse events queued while the Compositor is unavailable now fall back to
direct WebContent dispatch. This keeps input completion in step with the
pending-event queue.
Recovery is capped at three automatic restarts. If the restart limit is
exceeded, if restart, reconnect, or context recreation fails, or if the
replacement Compositor exits during active recovery, the browser crashes
instead of switching process-backed views to a fallback path.
We are moving toward an architecture where the browser owns a single
process that holds the GPU context, so Skia resources can be shared
across every renderer and WebContent processes can be sandboxed away
from direct GPU access. A dedicated Compositor helper process is the
first step. The earlier commits laid the foundation; this one turns the
helper on as a selectable backend, gated behind
--enable-compositor-process so the existing in-process path stays the
shipping default.
Default topology -- one compositor per WebContent, in-process:
+---------+
| Browser |
+---------+
/ | \
v v v
+---+ +---+ +---+ each WebContent runs its own
|WC | |WC | |WC | CompositorThread on a dedicated
|+C+| |+C+| |+C+| thread, with its own GPU context.
+---+ +---+ +---+
Opt-in topology -- one single-threaded Compositor, shared by all WCs:
+---------+ control +-------------------+
| Browser |<----------->| Compositor |
+---------+ | (single thread, |
/ | \ | single GPU ctx, |
v v v data | shared by all |
[WC] [WC] [WC] ---------->| connected WCs) |
+-------------------+
Three IPC channels carry the work in the opt-in topology. The
existing Browser<->WebContent channel gains context allocation.
A new Browser<->Compositor channel carries context lifetime,
viewport, UI input, and presentation acks plus backing-store and
frame upcalls. A new WebContent<->Compositor channel carries
display lists, scroll state, video, compositor surfaces, async
scrolling, presentation, and screenshots, with upcalls for
delegated input and compositor loss.
Add a repeatable blocker-list option that reads local list files in the
browser process. The files are concatenated into one buffer and shared
with WebContent through the content blocker IPC path when view options
are applied.
Parse the buffer in WebContent and reject malformed UTF-8 without
replacing the currently installed rules.
Load the browser-generated crash page as a synthetic response for the
URL that was active when WebContent exited. This keeps the session
history entry, response URL, and created Document aligned with the same
navigation URL, so reload targets the original page without creating a
local document for an HTTP(S) history entry.
Suppress history metadata updates from the generated page and declare
an inert rel=icon. Fallback favicon loading now follows the HTML
condition that no link with the icon keyword exists, which avoids the
credentialed /favicon.ico request from the crashed origin.
Route mouse events over the compositor IPC path while async scrolling is
enabled, and let the compositor capture viewport scrollbar drags before
the main-thread event path sees them. Dragging mutates the compositor
scroll tree and schedules an async-scroll present, so the viewport thumb
and content can move without a main-thread round trip.
Keep normal main-thread event handling for misses and preserve the wheel
bypass behavior for page events.
The synchronous wheel path treats wheel deltas as CSS-pixel scroll
distances, while the async compositor scroll tree mutates scroll state
stored in device pixels. Passing the same unscaled delta into the
compositor made async scrolling advance too little whenever
device pixels per CSSPixel was greater than 1, so scrolling felt slower
than with async scrolling disabled.
Convert wheel deltas before crossing the compositor boundary and make
the compositor IPC carry only the device-pixel position and delta it
needs. This keeps AsyncScrollTree device-pixel native and makes async
viewport scrolling match the synchronous path across high-DPI displays
and page zoom levels.
Trace the compositor state transitions that matter once presentation and
async scrolling share one path: page registration, backing-store swaps,
did_paint delivery, ready_to_paint acknowledgements, wheel admission,
and deferred presents waiting for reusable bitmaps.
Keep the logs under COMPOSITOR_DEBUG and use the [Compositor] prefix
consistently. The trace is about ownership and backpressure instead of
dumping every wheel event detail, so stalls can be diagnosed without
reintroducing noisy async-scrolling-only logging.
Send the experimental UI-process wheel bypass to WebContent over the
Compositor IPC connection instead of adding a separate async scrolling
transport. This keeps bypass admission on the channel that owns bitmaps
and ready_to_paint acknowledgements.
If the compositor rejects the wheel, LibWebView falls back to regular
input delivery. If it accepts, mark the queued DOM event as having
already performed its default action so dispatch preserves ordering
without scrolling twice.
Introduce a dedicated Compositor IPC channel between the UI process and
WebContent. Use it for backing-store setup, presented bitmap delivery,
and bitmap-specific ready_to_paint acknowledgements.
This makes CompositorThread the single owner of frame presentation
bookkeeping before async scrolling starts producing frames without the
main thread.
Remove old paint and backing-store messages from WebContentClient and
PageClient so the UI process no longer observes two presentation
protocols.
Remember the zoom level for each host so that returning to a site
restores the zoom the user previously chose, matching what other
browsers have done for years.
When the user zooms in, zooms out, or resets the zoom, the resulting
level is written to Settings keyed by the current page's host. On
navigation, when a view's URL host changes, the stored level for the
new host is applied (or the global default if there is no override).
Per-host zoom changes are broadcast through the SettingsObserver so
that two tabs viewing the same host stay in sync as soon as the user
adjusts zoom in either one. Zoom changes from within the page (such
as internals.setBrowserZoom hook) and the WebContent restart path do
not persist, only user-initiated zoom changes do.
Previously, if search was disabled, entering non-URL text would just
silently drop the search query (and on Qt, we would reload the current
URL). We now detect that the query did not result in a navigation and
load an error page instead, which directs the user to enable search.
Record visits as soon as a page produces useful metadata such as a
title or favicon so pages that never finish loading still become
autocomplete candidates.
Store favicons in the history schema from the start instead of
introducing an upgrade path inside this series, and cover persisted
metadata behavior in TestHistoryStore.
Generalize the backing store sharing abstraction into SharedImage, which
represents shared GPU memory independently of Skia and can be used to
share memory between different processes or different GPU contexts.
When a page opens a popup, the child tab shares the parent's
WebContent process via initialize_client_as_child(). Both tabs
register as views on the same WebContentClient.
If the child tab then does a cross-site navigation,
create_new_process_for_cross_site_navigation() would call
unregister_view() (correct) and then unconditionally send
CloseServer (wrong). This killed the WebContent process even
though the parent tab was still using it.
The unconditional async_close_server() predates the shared-process
popup model. It is no longer needed since unregister_view() already
sends CloseServer when the last view is removed.
