Remember view position after refreshing the page

Currently the view position is saved by a hash based on the file contents. When the page reloads, we should also take the last position into account, because it matches the normal behavior of browsers. Usually, when you reload a web page, the scroll offset is restored (even if the content of the page changed).

The motivation for this change comes from experiencing the following broken workflow:

1. Generate a local PDF file (file://....pdf).
2. Open PDF with PDF.js and scroll to some chapter in the PDF file.
3. Edit PDF file.
4. Refresh the PDF.js viewer (e.g. with F5).
5. Expected result: Retain the scroll position.
   Actual result: Page 1 is shown in the viewport.

Technical notes:

• performance.navigation.type can be used to detect page reload versus navigations.
• history.state is preserved when a page reloads.

[Rob--W]

@ankitverma2211 If possible, tests would be great. However, we don’t have automated tests for this kind of features, so if the patch looks reasonable and passes a manual test, then we would accept it too.

[allefeld]

I submitted a similar issue #11359 with respect to *latex-generated pdf. It is actually not correct that this uses a “hash based on the file contents” @Rob--W. Rather, it is an ID embedded in the PDF upon creation, and how that ID is generated depends on the generating application, for *latex it is a hash based on the combination of the current time and the pathname of the tex-file. See my last comment there for a solution.