Refer to below guide and check the Browser Setup section in order to enable Integrated Browser inside CAD. In case, if you already have enabled it and is not showing up in CAD then verify if the agents are under the correct workflow group or not from web based CDA
http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/crs/express_8_5/user/guide/cda85ccxug-cm.pdf
Regards
Deepak