This PR to improve the Scrollbar API to manage the state in the
internal.
## Break Changes
Describe any breaking changes introduced by this pull request. If none,
remove this section.
- Removed `scrollbar_state` argument from `Scrollbar::new`,
`Scrollbar::both`, `Scrollbar::vertical` and `Scrollbar::horizontal`.
```diff
- Scrollbar::horizontal(&self.scrollbar_state, &self.scroll_handle)
+ Scrollbar::horizontal(&self.scroll_handle)
- Scrollbar::vertical(&self.scrollbar_state, &self.scroll_handle)
+ Scrollbar::vertical(&self.scroll_handle)
```
- Change `struct ScrollbarState` to private, we not need this not.
```diff
- pub struct ScrollbarState {
+ struct ScrollbarState {
```
- Renamed `trait ScrollHandleOffsetable` to `trait ScrollbarHanle`.
```diff
- pub trait ScrollHandleOffsetable {
+ pub trait ScrollbarHanle {
```
- Removed `Scrollbar::both`, now use `Scrollbar::new` instead.
```diff
- Scrollbar::both(&scroll_handle)
+ Scrollbar::new(&scroll_handle)
```
4a3f520c5f