[Windows] Fix for Scrollview.ScrollTo execution only returns after manual scroll

[HarishwaranVijayakumar]

Root Cause of the issue

• When the scroll offset is set to the same value as the current view, the scroll view doesn't change. As a result, the scroll operation never completes, causing the await method to wait indefinitely. Consequently, the code after the await will not be executed.

Description of Change

• To address this issue, I have implemented a check to mark the scroll as finished when the requested offset is the same as the current platform offset

Issues Fixed

Fixes #15508

Tested the behaviour in the following platforms

• Windows
• Android
• iOS
• Mac

Output

Before Fix	After Fix
Beforefix_scroll.mp4	Afterfix_scroll.mp4

[dotnet-policy-service]

Hey there @HarishwaranVijayakumar! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

Pull Request Overview

This PR fixes an issue where ScrollView.ScrollTo on Windows would not complete the operation when the requested offset matched the current offset, causing the await to wait indefinitely.

• Added automated tests for the issue in both shared tests and the host app.
• Updated the Windows ScrollViewHandler to immediately mark scrolling as finished when the requested offset matches the current offset.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue15508.cs	Added a test that verifies the scroll operation completes as expected.
src/Controls/tests/TestCases.HostApp/Issues/Issue15508.cs	Implemented a UI test demonstrating the scroll fix in the host app.
src/Core/src/Handlers/ScrollView/ScrollViewHandler.Windows.cs	Updated scroll behavior to handle cases where the current offset matches the requested offset.

Comments suppressed due to low confidence (2)

src/Controls/tests/TestCases.HostApp/Issues/Issue15508.cs:29

• [nitpick] Consider renaming the local variable _scrollButton to scrollButton for clarity, reserving the underscore prefix for private fields.

Button _scrollButton = new Button

src/Core/src/Handlers/ScrollView/ScrollViewHandler.Windows.cs:77

• [nitpick] If VerticalOffset and HorizontalOffset are floating point values, consider using an epsilon-based comparison to handle potential precision issues.

if (request.VerticalOffset == handler.PlatformView.VerticalOffset && request.HorizontalOffset == handler.PlatformView.HorizontalOffset)