Migrate app startup snippets

[pengzhi-cb]

Code snippets are for:

1. (3 snippets) https://developer.android.com/topic/performance/appstartup/analysis-optimization
2. (2 snippets) https://developer.android.com/topic/performance/appstartup/best-practices

Total: 5 code snippets (3 unique Kotlin snippets and 0 XML snippets) across 2 pages.

List of modifications

1. Analysis-optimization page: Replaced standalone ... placeholders with // ... comments and added braces { ... } around the if (BuildConfig.DEBUG) body in MyApplication.onCreate() (android_performance_appstartup_strict_mode).
2. Analysis-optimization page: Normalized indentation to 4 spaces and added spaces inside { mutableStateOf(false) } in android_compose_performance_conditional_composition and android_compose_performance_conditional_composition_effect.
3. Best-practices page: Consolidated duplicate conditional composition blocks with the Analysis-optimization page by sharing android_compose_performance_conditional_composition and android_compose_performance_conditional_composition_effect in PerformanceSnippets.kt, and normalized indentation from 3 spaces to 4 spaces.

Snippets not migrated

1. Analysis-optimization page:
   1. None (all 3 snippets on the guide page were migrated).
2. Best-practices page:
   1. None (all 2 snippets on the guide page were migrated).

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• compose/snippets/src/main/java/com/example/compose/snippets/performance/AnalysisOptimization.kt:22, tag android_performance_appstartup_strict_mode
• compose/snippets/src/main/java/com/example/compose/snippets/performance/PerformanceSnippets.kt:284, tag android_compose_performance_conditional_composition
• compose/snippets/src/main/java/com/example/compose/snippets/performance/PerformanceSnippets.kt:292, tag android_compose_performance_conditional_composition_effect

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[kkuan2011]

Thanks Peng, could you rename the title of the PR to something like Migrate performance snippets? Also feel free to remove any comments in the PR description if it refers to intermediate states of the PR and is not reflected in the final code (e.g. mentions of System.gc() can be removed now). I've also added our Performance DRE, Ajesh, for review on the PR too.

[pengzhi-cb]

Thanks Peng, could you rename the title of the PR to something like Migrate performance snippets? Also feel free to remove any comments in the PR description if it refers to intermediate states of the PR and is not reflected in the final code (e.g. mentions of System.gc() can be removed now). I've also added our Performance DRE, Ajesh, for review on the PR too.

Got it, since the final diff wouldn't show those intermediary changes and it will be confusing to reviewer. Let me remove.

[kkuan2011]

actually instead of enabling this in the build file, can we handle this by declaring a mock object in the AnalysisOptimization file?

private object BuildConfig {
const val DEBUG = true
}

Because I think enabling this property can have build time implications for everyone using the snippets repo. And in the AGP 8.0 Release Notes, it looks like buildConfig is false by default to eliminate this compilation overhead.

[pengzhi-cb]

Revert in 6c8c78c

[kkuan2011]

Looks good after comments are addressed

[kkuan2011]

Looks good, thanks!