GitLab

Use IDL dictionary (NotificationOptions) instead of generic
Dictionary. Tests under fast/notifications are passed.

BUG=403150

Review URL: https://codereview.chromium.org/556193002

git-svn-id: svn://svn.chromium.org/blink/trunk@181879 bbb929c8-8fbe-4397-9dbb-9b2b20218538