Refactor FXIOS-14403 - [Performance] - Eliminate redundant blur view updates during BVC dismissal

[PARAIPAN9]

:scroll: Tickets

Jira ticket Github issue

:bulb: Description

• Performance profiling revealed that frequent calls to updateBlurViews were causing tab tray hangs during BVC dismissal. This PR eliminates unnecessary blur view updates during view controller transitions.

• Root Cause: updateBlurViews was invoked repeatedly during BVC dismissal, creating performance bottlenecks.

• As you can see, pretty bad hangs related to updateBlurViews method.

• Solution: Introduced a shouldLayoutSubviews flag that prevents blur view updates during transitions:

• When the tab tray button is tapped, viewDidLayoutSubviews was called approximately 2 times after viewWillDisappear.

• Each call triggered updateBlurViews, which was unnecessary during the transition animation.

• The new flag blocks these updates during BVC → Tab Tray transitions.

Hangs before these changes:

Hangs with changes in this PR.

• No more hangs related to updateBlurViews method, only micro hangs left to solve during presenting/dismissal animations.

:pencil: Checklist

• [x] I filled in the ticket numbers and a description of my work
• [x] I updated the PR name to follow our PR naming guidelines
• [x] I ensured unit tests pass and wrote tests for new code
• [x] If working on UI, I checked and implemented accessibility (Dynamic Text and VoiceOver)
• [x] If adding telemetry, I read the data stewardship requirements and will request a data review
• [x] If adding or modifying strings, I read the guidelines and will request a string review from l10n
• [x] If needed, I updated documentation and added comments to complex code

[PARAIPAN9]

Tested with these changes, did not see any regressions regarding translucency.

[mobiletest-ci-bot]

	Messages
:book:	Project coverage: 38.1%

🧹 Tidy commit

Just 1 file(s) touched. Thanks for keeping it clean and review-friendly!

💬 Description craftsman

Great PR description! Reviewers salute you 🫡

🦊 BrowserViewController Check

We’re tracking the size of BrowserViewController.swift to keep it healthy.

• ✨ Change in file size: +16 lines

❌ Per-file test coverage gate

The following changed file(s) are below 35.0% coverage:

File	Coverage	Required
firefox-ios/Client/Frontend/Browser/BrowserViewController/Views/BrowserViewController.swift	29.7%	35.0%

Client.app: Coverage: 37.28

File	Coverage
BrowserViewController.swift	29.68%	⚠️

Generated by :no_entry_sign: Danger Swift against ccb71e7d530178b929f372d3acd4c0edcf31fc0f

[thatswinnie]

We should wrab all changes in a toolbarTranslucencyRefactor check.

[PARAIPAN9]

Ok, I will.

[PARAIPAN9]

Closing... It is easier to fix some of the issues for isToolbarTranslucencyRefactorEnabled in a new PR.