Windows does not provide a system notification the embedder can
subscribe to to determine when a screen reader or other assistive
technology that requires the semantics tree has been enabled. [1]
In the absence of such a notification, we watch for queries for the
IAccessible COM object representing the root node of the semantics tree,
and on receipt of such queries we enable the semantics tree. For the
time being, we assume that if accessiblity is enabled, it will be
enabled for the duration of the application lifetime. In a future patch
we can optimise this by adopting the approach taken by Chromium, which
is to disable semantics if we haven't received a query within some
reasonable timeout.
This patch enables Flutter's semantics tree; a follow-up patch wires in
the AccessibilityBridge which maintains the AXTree of COM objects that
is the Windows representation of the Flutter SemanticsTree.
Issue: https://github.com/flutter/flutter/issues/77838
[1]: https://docs.microsoft.com/en-us/windows/win32/winauto/screen-reader-parameter
//flutter/third_party/accessiblity/ax/ax_event_generator.cc includes the
AXEventGenerator::Iterator class which subclasses std::iterator, which
triggers an MSVC C++17 deprecation warning. This warning, can be
suppressed by defining _SILENCE_CXX17_ITERATOR_BASE_CLASS_DEPRECATION_WARNING
which is already done in the accessibility_config config.
Also updates the TODO to reference the issue tracking the cleanup and
removal of that definition.
Issue: https://github.com/flutter/flutter/issues/92229
* [fuchsia] Keep track of all child transforms in FlatlandExternalViewEmbedder
(cherry picked from commit 0adc38c375cbc982c481771e76b0a464ce95ee79)
* [fuchsia] HandleRemoveview cleanup
The initial implementation tried to leverage the fuchsia.git approach to
adding resources via GN template, but the GN SDK does not use the same
format or approach. This PR adds the snapshot resource in the way the
GN SDK expects.
The integration test works in debug/jit mode only, and building in
`profile` and `release` modes was not working, breaking some builders.
The workaround was to disable the test.
This PR will enable release/aot mode so it will build, and unblock both
the debug-mode version of the test (tested by CI) and release mode
builds of the repo.
Due to the request to unblock, this PR does not yet build packages in
`profile` mode that will run in Fuchsia, but it should at least build
without errors. Ongoing work is in progress to also support running in
release mode.
