Introducing WTF::TypeSafeEnum and DatabaseError.
https://bugs.webkit.org/show_bug.cgi?id=108279.

Reviewed by Geoffrey Garen.

Source/WebCore: 

DatabaseError will be used later in the webdatabase refactoring effort.
It is currently unused.

No new tests.

* GNUmakefile.list.am:
* Modules/webdatabase/DatabaseError.h: Added.
(WebCore):
* Target.pri:
* WebCore.vcproj/WebCore.vcproj:
* WebCore.vcxproj/WebCore.vcxproj:
* WebCore.vcxproj/WebCore.vcxproj.filters:
* WebCore.xcodeproj/project.pbxproj:

Source/WTF: 

* WTF.xcodeproj/project.pbxproj:
* wtf/TypeSafeEnum.h: Added.
(WTF):
(TypeSafeEnum):
(WTF::TypeSafeEnum::TypeSafeEnum):
(WTF::TypeSafeEnum::value):
(WTF::TypeSafeEnum::operator==):
(WTF::TypeSafeEnum::operator!=):
(WTF::TypeSafeEnum::operator<):
(WTF::TypeSafeEnum::operator<=):
(WTF::TypeSafeEnum::operator>):
(WTF::TypeSafeEnum::operator>=):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141219 268f45cc-cd09-0410-ab3c-d52691b4dbfc