tdf#160982 wina11y: Drop extra screen reader check to enable a11y bridge

When initializing the a11y bridge on Windows, no longer
check whether the screen reader parameter
`SPI_GETSCREENREADER` [1] is explicitly set or require
to explicitly enable by setting an
`SAL_FORCE_IACCESSIBLE2` environment variable.

For performance reasons, it of course makes sense to only
enable the a11y bridge when there is actually assistive
technology that makes use of it.

However, `ImplInitAccessBridge` already only gets called
when either support for assistive technology has explicitly
been enabled in the settings (i.e. in "Tools" -> "Options" -> "LibreOfficeDev"
-> "Accessibility", the "Support assistive technology tools (restart
required" checkbox was checked) or when a `WM_GETOBJECT` message
is received, whose documentation says [2]:

> Sent by both Microsoft Active Accessibility and Microsoft UI Automation
> to obtain information about an accessible object contained in a server
> application.
>
> Applications never send this message directly. Microsoft Active
> Accessibility sends this message in response to calls to
> AccessibleObjectFromPoint, AccessibleObjectFromEvent, or
> AccessibleObjectFromWindow. However, server applications handle this
> message. UI Automation sends this message in response to calls to
> IUIAutomation::ElementFromHandle, ElementFromPoint, and
> GetFocusedElement, and when handling events for which a client has
> registered.

Both of these cases (explicitly enabled, AT requests information) justify
enabling the a11y bridge by themselves, so drop the extra check.

Qt's UIA bridge for example also gets activated when a WM_GETOBJECT
message is received [3].

This makes both, Microsoft Narrator (screen reader shipped with
Windows, but which doesn't set the `SPI_GETSCREENREADER` parameter)
and Microsoft Accessibility Insights for Windows (a tool for a11y
analysis/debugging) work - at least to a certain degree - without
having to explicitly set the environment variable
`SAL_FORCE_IACCESSIBLE2`.

While LibreOffice doesn't have a UIA bridge at this point in time,
Windows provides an MSAA (IAccessible) to UIA proxy that provides
some basic information via UIA at least, see [4]:

> The LegacyIAccessible control pattern is supported by the Microsoft
> Active Accessibility to Microsoft UI Automation Proxy.

As expected, a breakpoint or assert in `ImplInitAccessBridge`
only got hit in my testing when either an AT was active or the
above-mentioned option was explicitly enabled, not otherwise when
starting or using LO.

[1] https://learn.microsoft.com/en-us/windows/win32/winauto/screen-reader-parameter
[2] https://learn.microsoft.com/en-us/windows/win32/winauto/wm-getobject
[3] https://code.qt.io/cgit/qt/qtbase.git/tree/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp?id=e9662a4b665144a5eca418925d331024ec71fa2c#n40
[4] https://learn.microsoft.com/en-us/windows/win32/winauto/uiauto-implementinglegacyiaccessible

Change-Id: Iddafb149b50771412ba59972d0401bada6a9f680
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/175172
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

0 files changed, 0 insertions, 0 deletions