* Electron version: 1.4.15
* Operating system: Windows 10

### Actual behavior

Height is oversized by exactly 8px consistently (taskbar is set to small icons).

![Alt](https://raw.githubusercontent.com/adi518/electron-frameless-maximize-test/master/issue.jpg)

### How to reproduce

https://github.com/adi518/electron-frameless-maximize-test
atom/browser/native_window_views.cc
#if defined(OS_WIN)
  if (has_frame())
    FlipWindowStyle(GetAcceleratedWidget(), resizable, WS_THICKFRAME);
#elif defined(USE_X11)
  if (resizable != resizable_) {
    
    
    if (resizable) {
      SetContentSizeConstraints(old_size_constraints_);
    } else {
      old_size_constraints_ = GetContentSizeConstraints();
      resizable_ = false;
      gfx::Size content_size = GetContentSize();
      SetContentSizeConstraints(
          extensions::SizeConstraints(content_size, content_size));
    }
  }
#endif
  resizable_ = resizable;
}
bool NativeWindowViews::IsResizable() {