* Output of `node_modules/.bin/electron --version`: 2.0.12
* Operating System (Platform and Version): Windows 10

**Expected Behavior**
`moveItemToTrash` should return `false` if the file is locked.

**Actual behavior**
`moveItemToTrash` does not return `false` when a file is locked.

**To Reproduce**
* open a folder in a command prompt (cd into it)
* run `shell.moveItemToTrash(path of folder)`
* observe the returned value is `true` indicating this operation was successful
shell/common/platform_util_win.cc
return S_OK;
}
HRESULT DeleteFileProgressSink::PostRenameItem(DWORD,
                                               IShellItem*,
                                               __RPC__in_string LPCWSTR,
                                               HRESULT,
                                               IShellItem*) {
  return E_NOTIMPL;
}
HRESULT DeleteFileProgressSink::PreMoveItem(DWORD,
                                            IShellItem*,
                                            IShellItem*,
                                            LPCWSTR) {
  return E_NOTIMPL;
}
HRESULT DeleteFileProgressSink::PostMoveItem(DWORD,
                                             IShellItem*,
                                             IShellItem*,
                                             LPCWSTR,
                                             HRESULT,
                                             IShellItem*) {
  return E_NOTIMPL;
}
HRESULT DeleteFileProgressSink::PreCopyItem(DWORD,
                                            IShellItem*,
                                            IShellItem*,
                                            LPCWSTR) {
  return E_NOTIMPL;
}
HRESULT DeleteFileProgressSink::PostCopyItem(DWORD,