… in advanced chart cp-7.74.0 (#28985)

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## **Description**

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2. What is the improvement/solution?
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This PR fixes a post-merge regression in the advanced chart timeframe
switch flow. After the recent remount based fix, there was still a race
where a new OHLCV response could arrive before the remounted WebView
finished loading. In that case, the stale snapshot guard could
misclassify the already fresh candle array as stale and never send
SET_OHLCV_DATA, leaving the new chart instance without data.

The fix narrows the stale snapshot logic so it captures only the
previously synced OHLCV array at the moment the series key changes,
instead of marking again whatever data happens to be in props later.
This preserves the original protection against sending the previous
range into the new WebView, while also allowing fast new range responses
to sync correctly as soon as the remounted WebView finishes loading.

The PR also adds a focused regression test covering the fast-response /
delayed-WebView-load case.

## **Changelog**

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CHANGELOG entry: Covered fast response / delayed WebView load case in
stale snapshot guard

## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

## **Screenshots/Recordings**

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### **Before**

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### **After**

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https://github.com/user-attachments/assets/a8ede52e-3699-4c9d-9dc3-c3051dfd0cf7



## **Pre-merge author checklist**

- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I've included tests if applicable
- [ ] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

#### Performance checks (if applicable)

- [ ] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [ ] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [ ] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Touches chart data synchronization and remount timing logic, which can
impact whether users see up-to-date candles during timeframe switches.
Changes are localized and backed by a targeted regression test.
> 
> **Overview**
> Fixes a timeframe-switch race in `AdvancedChart` where a fast new
`ohlcvData` response could be incorrectly treated as “stale” during a
WebView remount, preventing `SET_OHLCV_DATA` from ever being sent.
> 
> The stale-snapshot guard is tightened to snapshot the *previously
synced* OHLCV array at the moment `ohlcvSeriesKey` changes (instead of
whatever happens to be in props later), and the extra early-return path
on series-key change is removed so fresh data can sync once the new
WebView finishes loading. Adds a regression test covering “fresh data
arrives before `onLoadEnd` after series change.”
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
7c5303f. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: sahar-fehri <sahar.fehri@consensys.net>