SecurityOrigin doesn’t need to forward declare or include Document
https://bugs.webkit.org/show_bug.cgi?id=115847

Reviewed by Alexey Proskuryakov.

Merge https://chromium.googlesource.com/chromium/blink/+/fc7a88caa9c41f3471d8994a530643e5225f82fc.

Removed unused Document forward declaration+include from SecurityOrigin.

* page/SecurityOrigin.cpp:
* page/SecurityOrigin.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149791 268f45cc-cd09-0410-ab3c-d52691b4dbfc