### Issue Details
in frameless windows 
While setting browserview style to draggable by webkit-app-region : drag. the area won't be draggable after that
and it can not move main window 
### Electron Version:
11.0.1
### Operating System:
Windows 10 (1803)
Last Known Working Electron version:
not found
### Expected Behavior
Browser view moves the main window while I set the style of the body or one of the area to
-webkit-app-region: drag;

### Actual Behavior
nothing happen in browserview after styling -webkit-app-region: drag;

I know it is mention that in 11 version it is fixed. but it still dosn't work 

### To Reproduce
https://gist.github.com/pejmanpesyan/8540aad65e7c6980c45f23e5eaafafb9

shell/browser/native_window_views.cc
#elif defined(OS_WIN)
#include "base/win/win_util.h"
#include "shell/browser/ui/views/win_frame_view.h"
#include "shell/browser/ui/win/electron_desktop_native_widget_aura.h"
#include "skia/ext/skia_utils_win.h"
#include "ui/base/win/shell.h"
#include "ui/display/screen.h"
#include "ui/display/win/screen_win.h"
#include "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
#endif
namespace electron {
namespace {
#if defined(OS_WIN)
const LPCWSTR kUniqueTaskBarClassName = L"Shell_TrayWnd";
void FlipWindowStyle(HWND handle, bool on, DWORD flag) {
  DWORD style = ::GetWindowLong(handle, GWL_STYLE);
  if (on)
    style |= flag;
  else
    style &= ~flag;
  ::SetWindowLong(handle, GWL_STYLE, style);
}
gfx::Rect ScreenToDIPRect(HWND hwnd, const gfx::Rect& pixel_bounds) {
  float scale_factor = display::win::ScreenWin::GetScaleFactorForHWND(hwnd);
  gfx::Rect dip_rect = ScaleToRoundedRect(pixel_bounds, 1.0f / scale_factor);
  dip_rect.set_origin(
      display::win::ScreenWin::ScreenToDIPRect(hwnd, pixel_bounds).origin());
  return dip_rect;
}
gfx::Rect DIPToScreenRect(HWND hwnd, const gfx::Rect& pixel_bounds) {