Whenever I click on PDF file within a Safari - I have always had it open within the Safari Browser.
It does not open anylonger within the safari. Please let me know if there is some settings I need to enable to restore PDF open within the browser.
Open the Finder. From the Finder menu bar click Go > Go to Folder
Type of copy / paste: /Library/Internet Plug-Ins
Click Go the move the Adobe PDF browser (or just PDF browser) plugin to the Trash.
Quit and relaunch Safari to test.