Rewrite the MSAA/UIA integration into conhost (#19344)

Goal: Remove `CursorBlinker`.
Problem: Spooky action at a distance via `Cursor::HasMoved`.
Solution: Moved all the a11y event raising into `_stream.cpp` and pray
for the best.

Goal: Prevent node.js from tanking conhost performance via MSAA (WHY).
Problem: `ServiceLocator`.
Solution: Unserviced the locator. Debounced event raising. Performance
increased by >10x.
Problem 2: Lots of files changed.

This PR is a prerequisite for #19330

## Validation Steps Performed
Ran NVDA with and without UIA enabled and with different delays. ✅

Author: lhecker

.github/actions/spelling/expect/expect.txt

@@ -807,6 +807,7 @@ IMPEXP
 inbox
 inclusivity
 INCONTEXT
+INDEXID
 INFOEX
 inheritcursor
 INITCOMMONCONTROLSEX
@@ -908,6 +909,7 @@ LNM
 LOADONCALL
 LOBYTE
 localappdata
+LOCATIONCHANGE
 locsrc
 Loewen
 LOGBRUSH
@@ -1033,6 +1035,7 @@ MOUSEACTIVATE
 MOUSEFIRST
 MOUSEHWHEEL
 MOVESTART
+msaa
 msb
 msbuildcache
 msctls
@@ -1973,8 +1976,8 @@ WRITECONSOLEINPUT
 WRITECONSOLEOUTPUT
 WRITECONSOLEOUTPUTSTRING
 wrkstr
-WRL
 wrl
+WRL
 wrp
 WRunoff
 WSLENV

dep/Console/ntcsrdll.h

@@ -7,9 +7,17 @@ Licensed under the MIT license.
 
 #include <ntcsrmsg.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 NTSTATUS CsrClientCallServer(
     PCSR_API_MSG m,
     PCSR_CAPTURE_HEADER CaptureBuffer OPTIONAL,
     ULONG ApiNumber,
     ULONG ArgLength
 );
+
+#ifdef __cplusplus
+}
+#endif

dep/Console/ntlpcapi.h

@@ -5,6 +5,10 @@ Licensed under the MIT license.
 
 #pragma once
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define OB_FILE_OBJECT_TYPE 1
 
 typedef struct _PORT_MESSAGE {
@@ -124,3 +128,7 @@ NTSTATUS NtAlpcQueryInformationMessage(
     ULONG Length,
     PULONG ReturnLength
 );
+
+#ifdef __cplusplus
+}
+#endif

src/buffer/out/cursor.cpp

@@ -13,7 +13,6 @@
 // - ulSize - The height of the cursor within this buffer
 Cursor::Cursor(const ULONG ulSize, TextBuffer& parentBuffer) noexcept :
     _parentBuffer{ parentBuffer },
-    _fHasMoved(false),
     _fIsVisible(true),
     _fIsOn(true),
     _fIsDouble(false),
@@ -35,11 +34,6 @@ til::point Cursor::GetPosition() const noexcept
     return _cPosition;
 }
 
-bool Cursor::HasMoved() const noexcept
-{
-    return _fHasMoved;
-}
-
 bool Cursor::IsVisible() const noexcept
 {
     return _fIsVisible;
@@ -75,11 +69,6 @@ ULONG Cursor::GetSize() const noexcept
     return _ulSize;
 }
 
-void Cursor::SetHasMoved(const bool fHasMoved) noexcept
-{
-    _fHasMoved = fHasMoved;
-}
-
 void Cursor::SetIsVisible(const bool fIsVisible) noexcept
 {
     _fIsVisible = fIsVisible;
@@ -249,7 +238,6 @@ void Cursor::CopyProperties(const Cursor& OtherCursor) noexcept
     // We shouldn't copy the position as it will be already rearranged by the resize operation.
     //_cPosition                    = pOtherCursor->_cPosition;
 
-    _fHasMoved = OtherCursor._fHasMoved;
     _fIsVisible = OtherCursor._fIsVisible;
     _fIsOn = OtherCursor._fIsOn;
     _fIsDouble = OtherCursor._fIsDouble;

src/buffer/out/cursor.h

@@ -38,7 +38,6 @@ class Cursor final
     Cursor(Cursor&&) = default;
     Cursor& operator=(Cursor&&) & = delete;
 
-    bool HasMoved() const noexcept;
     bool IsVisible() const noexcept;
     bool IsOn() const noexcept;
     bool IsBlinkingAllowed() const noexcept;
@@ -54,7 +53,6 @@ class Cursor final
     bool IsDeferDrawing() noexcept;
     void EndDeferDrawing() noexcept;
 
-    void SetHasMoved(const bool fHasMoved) noexcept;
     void SetIsVisible(const bool fIsVisible) noexcept;
     void SetIsOn(const bool fIsOn) noexcept;
     void SetBlinkingAllowed(const bool fIsOn) noexcept;
@@ -90,7 +88,6 @@ class Cursor final
 
     til::point _cPosition; // current position on screen (in screen buffer coords).
 
-    bool _fHasMoved;
     bool _fIsVisible; // whether cursor is visible (set only through the API)
     bool _fIsOn; // whether blinking cursor is on or not
     bool _fIsDouble; // whether the cursor size should be doubled

src/cascadia/TerminalCore/Terminal.hpp

@@ -154,7 +154,6 @@ class Microsoft::Terminal::Core::Terminal final :
     void UseMainScreenBuffer() override;
 
     bool IsVtInputEnabled() const noexcept override;
-    void NotifyAccessibilityChange(const til::rect& changedRect) noexcept override;
     void NotifyBufferRotation(const int delta) override;
     void NotifyShellIntegrationMark() override;
 

src/cascadia/TerminalCore/TerminalApi.cpp

@@ -347,11 +347,6 @@ bool Terminal::IsVtInputEnabled() const noexcept
     return false;
 }
 
-void Terminal::NotifyAccessibilityChange(const til::rect& /*changedRect*/) noexcept
-{
-    // This is only needed in conhost. Terminal handles accessibility in another way.
-}
-
 void Terminal::InvokeCompletions(std::wstring_view menuJson, unsigned int replaceLength)
 {
     if (_pfnCompletionsChanged)