doc-view-continuous is a variable defined in `doc-view.el'.
Its value is

In Continuous mode reaching the page edge advances to next/previous page.
When non-nil, scrolling a line upward at the bottom edge of the page
moves to the next page, and scrolling a line downward at the top edge
of the page moves to the previous page.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 23.2 of Emacs.