https://bugs.webkit.org/show_bug.cgi?id=120395

Reviewed by Christophe Dumez.

WorkerGlobalScopeDatabase uses the WorkerGlobalScope object which is
defined only when WORKERS are enabled. We should guard that code.

* Modules/webdatabase/WorkerGlobalScopeWebDatabase.cpp:
* Modules/webdatabase/WorkerGlobalScopeWebDatabase.h:
* Modules/webdatabase/WorkerGlobalScopeWebDatabase.idl:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154732 268f45cc-cd09-0410-ab3c-d52691b4dbfc