function enabledBreakpointCount(breakpoints)
        {
            var count = 0;
            for (var i = 0; i < breakpoints.length; ++i) {
                if (breakpoints[i].checkbox.checked)
                    count++;
            }
            return count;
        }
@param {!WebInspector.BreakpointManager.Breakpoint} breakpoint
@param {!Event} event