Remove unnecessary dependecy on CoreFoundation from WebDatabaseManager
https://bugs.webkit.org/show_bug.cgi?id=115993

Reviewed by Anders Carlsson.

Using COMPropertyBag instead of CFDictionaryPropertyBag also reduces
the total lines of code needed for the same functionality.

* WebDatabaseManager.cpp:
(WebDatabaseManager::dispatchDidModifyDatabase):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150115 268f45cc-cd09-0410-ab3c-d52691b4dbfc