[MSCTFIME][SDK] Add CInputContextOwner (stub) (#6584)

Supporting TIPs...
JIRA issue: CORE-19360
- Add ITfContextOwner
  interface to "msctf.idl".
- Stub-implement
  CInputContextOwner class.

sdk/include/psdk/msctf.idl

@@ -950,6 +950,38 @@ interface ITfTextEditSink : IUnknown
         [in] ITfEditRecord *pEditRecord);
 }
 
+[
+    object,
+    uuid(AA80E80C-2021-11D2-93E0-0060B067B86E),
+    pointer_default(unique)
+]
+interface ITfContextOwner : IUnknown
+{
+    HRESULT GetACPFromPoint(
+        [in]  const POINT *ptScreen,
+        [in]  DWORD       dwFlags,
+        [out] LONG        *pacp);
+
+    HRESULT GetTextExt(
+        [in]  LONG acpStart,
+        [in]  LONG acpEnd,
+        [out] RECT *prc,
+        [out] BOOL *pfClipped);
+
+    HRESULT GetScreenExt(
+        [out] RECT *prc);
+
+    HRESULT GetStatus(
+        [out] TF_STATUS *pdcs);
+
+    HRESULT GetWnd(
+        [out] HWND *phwnd);
+
+    HRESULT GetAttribute(
+        [in]  REFGUID rguidAttribute,
+        [out] VARIANT *pvarValue);
+}
+
 [
     object,
     uuid(5F20AA40-B57A-4F34-96AB-3576F377CC79),