add "time since launch" to telemetry

Author: vzaidman

front_end/core/host/RNPerfMetrics.ts

@@ -331,6 +331,7 @@ class RNPerfMetrics {
 
   #decorateEvent(event: ReactNativeChromeDevToolsEvent): Readonly<DecoratedReactNativeChromeDevToolsEvent> {
     const commonFields: CommonEventFields = {
+      timeSinceLaunch: performance.now(),
       timestamp: getPerfTimestamp(),
       launchId: this.#launchId,
       appId: this.#appId,
@@ -370,6 +371,7 @@ function maybeWrapError(baseMessage: string, error: unknown): [string, Error] {
 type EntryPoint = 'rn_fusebox'|'rn_inspector';
 
 type CommonEventFields = Readonly<{
+  timeSinceLaunch: DOMHighResTimeStamp,
   timestamp: DOMHighResTimeStamp,
   launchId: string | void | null,
   appId: string | void | null,