Define "Safari like".
If you just want rounded ends, that's an option on NSTextField/NSTextFieldCell that can be set programatically (check the headers) or in IB.
If you want the X button that appears once you type something, or the icon-and-popup-menu on the left, you're on your own -- common as they are lately, Apple doesn't provide these in any public API. They're not too difficult to do yourself, though; you could subclass NSTextFieldCell and add custom buttons as standardized subviews, and subclass NSTextFieldCell to make sure the text doesn't overlap them.
If you want a widget you can just plop into your app to provide Google searching... you've got quite a job ahead of you.