Remove deprecated WebIDB Type enums

These are replaced by the enums in WebIDBTypes.h

R=alecflett

Review URL: https://chromiumcodereview.appspot.com/19775007

git-svn-id: svn://svn.chromium.org/blink/trunk@154551 bbb929c8-8fbe-4397-9dbb-9b2b20218538