Fix IllegalStateException when starting a trace before Firebase init (firebase#6371)

Fix IllegalStateException when starting a trace before Firebase initializes. This can happen if you manually initialize Firebase. See firebase#4693

Author: mrober

firebase-perf/CHANGELOG.md

@@ -1,4 +1,5 @@
 # Unreleased
+* [fixed] Fix IllegalStateException when starting a trace before Firebase initializes.
 * [changed] Updated protobuf dependency to `3.25.5` to fix
  [CVE-2024-7254](https://github.com/advisories/GHSA-735f-pc8j-v9w8).
 

firebase-perf/src/main/java/com/google/firebase/perf/config/RemoteConfigManager.java

@@ -88,7 +88,13 @@ private RemoteConfigManager() {
  @VisibleForTesting
  @SuppressWarnings("FirebaseUseExplicitDependencies")
  static long getInitialStartupMillis() {
- StartupTime startupTime = FirebaseApp.getInstance().get(StartupTime.class);
+ StartupTime startupTime = null;
+ try {
+ startupTime = FirebaseApp.getInstance().get(StartupTime.class);
+ } catch (IllegalStateException ex) {
+ // This can happen if you start a trace before Firebase is init
+ logger.debug("Unable to get StartupTime instance.");
+ }
  if (startupTime != null) {
  return startupTime.getEpochMillis();
  } else {