Is this a bug report?

Yes

Environment

• react-native -v: 0.46

• Target Platform: Android

• Development Operating System: macOS

Steps to Reproduce

Systrace module in RN depends on hooks like nativeTraceBeginSection to exists (see https://github.com/facebook/react-native/blob/master/Libraries/Performance/Systrace.js#L134). But they are added here which isn't run becuase it requires fbsystrace.h to exist.

1. Try to use Systrace module. Fails because it's missing nativeTraceBeginSection and/or nativeTraceBeginSection
2. Try to add those by enabling WITH_JSC_EXTRA_TRACING. Fails because it's missing fbsystrace.h

Expected Behavior

Would be really helpful to be able to see what JSC is doing within a systrace on android