[MSCTF] Make thread manager C++ (#8239)

Implemeting missing features...
JIRA issue: CORE-19361
- Delete threadmgr.c and add threadmgr.cpp.
- Make ITfThreadMgr implementation C++.

base/ctf/msctf/CMakeLists.txt

@@ -6,7 +6,6 @@ spec2def(msctf.dll msctf.spec ADD_IMPORTLIB)
 
 list(APPEND SOURCE
     msctf.c
-    threadmgr.c
     precomp.h
     ${CMAKE_CURRENT_BINARY_DIR}/msctf_stubs.c)
 
@@ -20,6 +19,7 @@ list(APPEND PCH_SKIP_SOURCE
     langbarmgr.cpp
     mlng.cpp
     range.cpp
+    threadmgr.cpp
     utils.cpp)
 
 add_library(msctf MODULE