Lets check function declaration in d9 and in xe2:
Delphi9
Delphi XE2Code:function ReadProcessMemory(hProcess: THandle; const lpBaseAddress: Pointer; lpBuffer: Pointer; nSize: DWORD; var lpNumberOfBytesRead: DWORD): BOOL; stdcall; function WriteProcessMemory(hProcess: THandle; const lpBaseAddress: Pointer; lpBuffer: Pointer; nSize: DWORD; var lpNumberOfBytesWritten: DWORD): BOOL; stdcall;
var lpNumberOfBytesWritten: DWORD - var lpNumberOfBytesWritten: SIZE_TCode:function ReadProcessMemory(hProcess: THandle; const lpBaseAddress: Pointer; lpBuffer: Pointer; nSize: SIZE_T; var lpNumberOfBytesRead: SIZE_T): BOOL; stdcall; function WriteProcessMemory(hProcess: THandle; const lpBaseAddress: Pointer; lpBuffer: Pointer; nSize: SIZE_T; var lpNumberOfBytesWritten: SIZE_T): BOOL; stdcall;
So, replacing dwords into SIZE_T is correct