Description

This PR adds a fully optional performance profiling layer to the WooCommerce iOS app.

The goal is to give maintainers and contributors a clean, isolated and reusable way to:

• Emit os_signpost events for Instruments.
• Run repeatable UI performance tests on common user flows.
• Experiment with background image decoding via an opt-in cache.

What this PR does

• Adds PerformanceLogger

  • File: WooCommerce/Classes/Profiling/PerformanceLogger.swift
  • Central helper around os_signpost with several predefined categories (catalog load, image decode, cart / checkout, etc.).
  • Self-contained and only used when explicitly called.
  • Does not change any existing behavior by default.

• Adds OptimizedImageCache (optional micro-optimization)

  • File: WooCommerce/Classes/Profiling/OptimizedImageCache.swift
  • Background image decoding on a dedicated queue, storing fully decoded UIImages in an NSCache.
  • Exposed via a simple image(for:sourceProvider:completion:) API.
  • Not wired into existing views – can be adopted incrementally where appropriate.

• Adds UI performance tests

  • File: WooCommerce/WooCommerceUITests/Performance/PerformanceUITests.swift
  • Five scenarios using XCTMetric:
    • Browsing the product catalog.
    • Adding products to cart.
    • Completing checkout.
    • Image loading stress test.
    • Cold start performance.
  • Designed to be safe to run locally or in CI.

• Adds a profiling helper script

  • File: Scripts/profiling/run_profiling.sh
  • Optional script to:
    • Build the app and UI tests.
    • Run selected performance scenarios on a simulator.
    • Organize results under profiling_results/<timestamp>/.

• Updates .gitignore

  • Ignores profiling_results/ to avoid committing trace bundles and profiling artifacts.

Why it’s safe

• Only new files plus a minimal .gitignore update.
• No existing controllers, views or models are modified.
• No changes to build settings, dependencies or user-facing behavior.
• All profiling utilities live under dedicated Profiling / Performance groups and are completely opt-in.

Test Steps

To validate this change:

1. Build the app and tests

   • Open WooCommerce.xcworkspace in Xcode.
   • Select the WooCommerce scheme.
   • Run Product → Build and confirm it succeeds.
   • Select the WooCommerceUITests scheme and build as well.

2. Run a performance UI test from Xcode

   • With the WooCommerceUITests scheme selected:
   • In the Test navigator, locate PerformanceUITests.
   • Run, for example, testScenario1_BrowseProductCatalog on an iOS Simulator (e.g. iPhone 15).
   • Confirm the test passes and metrics are reported.

3. (Optional) Run all scenarios via the script

   • From the project root:
     • Ensure the script is executable:
       chmod +x Scripts/profiling/run_profiling.sh
     • Run:
       ./Scripts/profiling/run_profiling.sh all
   • Verify that:
     • The run completes without errors.
     • A new folder is created under profiling_results/<timestamp>/ containing traces / logs.