Fix the Windows build after r185721

[Csaba Osztrogonác]

https://trac.webkit.org/changeset/185721 broke the WinCairo build:
https://build.webkit.org/builders/WinCairo%2064-Bit%20Release/builds/46563

..\..\win\DumpRenderTree.cpp(1372): error C2259: 'UIDelegate' : cannot instantiate abstract class [C:\Users\Alex\Documents\WinCairoBot\win-cairo-release\build\Tools\DumpRenderTree\DumpRenderTree.vcxproj\DumpRenderTree\DumpRenderTree.vcxproj]
          due to following members:
          'HRESULT IWebUIDelegatePrivate::unused4(void)' : is abstract
          C:\Users\Alex\Documents\WinCairoBot\win-cairo-release\build\WebKitBuild\Release_WinCairo\Include\WebKit/WebKit.h(33580) : see declaration of 'IWebUIDelegatePrivate::unused4'

[Csaba Osztrogonác]

Not only the WinCairo build, but Apple Windows build is broken too:
https://build.webkit.org/builders/Apple%20Win%20Release%20%28Build%29/builds/70926

But unfortunately you weren't able to notice it before 
landing, because Windows EWS is broken a week ago.

I had the same problem as the Windows EWS locally, I had to run the command cpan LWP::Protocol::https from the shell.

Created attachment 255188 [details]
Patch

[Csaba Osztrogonác]

Comment on attachment 255188 [details]
Patch

rs=me

(In reply to comment #4)
> Comment on attachment 255188 [details]
> Patch
> 
> rs=me

Thanks!

[WebKit Commit Bot]

Comment on attachment 255188 [details]
Patch

Clearing flags on attachment: 255188

Committed r185747: <http://trac.webkit.org/changeset/185747>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.