[PDFHistory] Prevent updating the current position when zooming the document without scrolling the destination into view

__Steps to reproduce:__
1. Open: https://www.eff.org/sites/default/files/filenode/DMCA/NTIA%20DMCA%20White%20Paper.pdf.
2. Take note of the current zoom value.
3. Click on any item in the outline.
4. Click the back button in the browser.

__Expected result:__
The document should go back to the previous position, with the same zoom value as before.

__Actual result:__
The zoom value is wrong.