Smart GoogleDoc-like scroll bar for smartphones

As a mobile app user I miss a critical feature that reduces user experience friction.

That feature consists on having a smart scroll bar that allows to see at a glance all the elements of a table of contents and jump.

Use case or problem

Currently, you just have a row page, for which you have to scroll manually to find content. This can be horrible for long documents.

Proposed solution

Have a smart scroll bar like Google Docs app to have an eagle view of what the user is currently seeing in a page when scrolling.