Reviewed by Eric Seidel.

        Add #if ENABLE(DATABASE) guards around database code so toggling ENABLE_DATABASE off does not break builds.
        https://bugs.webkit.org/show_bug.cgi?id=24776

        No functional changes, thus no tests.

        * bindings/js/JSCustomSQLStatementCallback.cpp:
        * bindings/js/JSCustomSQLStatementCallback.h:
        * bindings/js/JSCustomSQLStatementErrorCallback.cpp:
        * bindings/js/JSCustomSQLStatementErrorCallback.h:
        * bindings/js/JSCustomSQLTransactionCallback.cpp:
        * bindings/js/JSCustomSQLTransactionCallback.h:
        * bindings/js/JSCustomSQLTransactionErrorCallback.cpp:
        * bindings/js/JSCustomSQLTransactionErrorCallback.h:
        * bindings/js/JSDatabaseCustom.cpp:
        * bindings/js/JSSQLTransactionCustom.cpp:
        * loader/EmptyClients.h:
        * page/ChromeClient.h:
        * storage/ChangeVersionWrapper.cpp:
        * storage/ChangeVersionWrapper.h:
        * storage/Database.cpp:
        (WebCore::Database::databaseInfoTableName):
        * storage/Database.h:
        * storage/Database.idl:
        * storage/DatabaseTask.cpp:
        * storage/DatabaseTask.h:
        * storage/DatabaseThread.cpp:
        * storage/DatabaseThread.h:
        * storage/DatabaseTracker.cpp:
        * storage/DatabaseTracker.h:
        * storage/DatabaseTrackerClient.h:
        * storage/OriginQuotaManager.cpp:
        * storage/OriginQuotaManager.h:
        * storage/SQLStatement.cpp:
        * storage/SQLStatement.h:
        * storage/SQLTransaction.cpp:
        * storage/SQLTransaction.h:
        * storage/SQLTransaction.idl:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@43283 268f45cc-cd09-0410-ab3c-d52691b4dbfc