feat: use scoped field in trace events to propagate stack traces

front_end/models/trace/extras/StackTraceForEvent.ts

@@ -50,6 +50,46 @@ export function get(event: Types.Events.Event, parsedTrace: Handlers.Types.Parse
   return result;
 }
 
+export function getForReactNative(event: Types.Events.Event, parsedTrace: Handlers.Types.ParsedTrace): Protocol.Runtime.StackTrace |
+null {
+  let cacheForTrace = stackTraceForEventInTrace.get(parsedTrace);
+  if (!cacheForTrace) {
+    cacheForTrace = new Map();
+    stackTraceForEventInTrace.set(parsedTrace, cacheForTrace);
+  }
+  const resultFromCache = cacheForTrace.get(event);
+  if (resultFromCache) {
+    return resultFromCache;
+  }
+  let result: Protocol.Runtime.StackTrace|null = null;
+
+  if (Types.Events.isUserTiming(event) && Types.Events.isPerformanceMeasureBegin(event)) {
+    result = extractStackTraceForReactNative(event);
+  } else if (Types.Extensions.isSyntheticExtensionEntry(event)) {
+    result = extractStackTraceForReactNative(event.rawSourceEvent);
+  } else if (Types.Events.isConsoleTimeStamp(event)) {
+    result = extractStackTraceForReactNative(event);
+  }
+
+  if (result) {
+    cacheForTrace.set(event, result);
+  }
+  return result;
+}
+
+export function extractStackTraceForReactNative(event: Types.Events.Event): Protocol.Runtime.StackTrace | null {
+  const data = event.args?.data;
+  if (!data) {
+    return null;
+  }
+
+  if (!data.rnStackTrace) {
+    return null;
+  }
+
+  return data.rnStackTrace;
+}
+
 function getForProfileCall(
     event: Types.Events.SyntheticProfileCall, parsedTrace: Handlers.Types.ParsedTrace): Protocol.Runtime.StackTrace {
   // When working with a CPU profile the renderer handler won't have

front_end/models/trace/types/TraceEvents.ts

@@ -93,6 +93,8 @@ export interface Args {
 
 export interface ArgsData {
   stackTrace?: CallFrame[];
+  // [RN] Custom field for linking stack traces to User Timings and TimeStamp events.
+  rnStackTrace?: Protocol.Runtime.StackTrace;
   sampleTraceId?: number;
   url?: string;
   navigationId?: string;

front_end/panels/timeline/TimelineUIUtils.ts

@@ -1838,22 +1838,32 @@ export class TimelineUIUtils {
     const {startTime} = Trace.Helpers.Timing.eventTimingsMilliSeconds(event);
     let initiatorStackLabel = i18nString(UIStrings.initiatorStackTrace);
     let stackLabel = i18nString(UIStrings.stackTrace);
-    const stackTraceForEvent = Trace.Extras.StackTraceForEvent.get(event, parsedTrace);
+
     // [RN] Used to scope down available features for React Native targets
     // See https://docs.google.com/document/d/1_mtLIHEd9bFQN4xWBSVDR357GaRo56khB1aOxgWDeu4/edit?tab=t.0 for context.
     const isReactNative = Root.Runtime.experiments.isEnabled(
         Root.Runtime.ExperimentName.REACT_NATIVE_SPECIFIC_UI,
     );
-    if (stackTraceForEvent && !isReactNative) {
-      contentHelper.addSection(i18nString(UIStrings.stackTrace));
-      contentHelper.createChildStackTraceElement(stackTraceForEvent);
-      // TODO(andoli): also build stack trace component for other events
-      // that have a stack trace using the StackTraceForEvent helper.
-    } else if (!isReactNative) {
-      const stackTrace = Trace.Helpers.Trace.getZeroIndexedStackTraceForEvent(event);
-      if (stackTrace?.length) {
-        contentHelper.addSection(stackLabel);
-        contentHelper.createChildStackTraceElement(TimelineUIUtils.stackTraceFromCallFrames(stackTrace));
+    if (isReactNative) {
+      const rnStackTrace = Trace.Extras.StackTraceForEvent.getForReactNative(event, parsedTrace);
+
+      if (rnStackTrace) {
+        contentHelper.addSection(i18nString(UIStrings.stackTrace));
+        contentHelper.createChildStackTraceElement(rnStackTrace);
+      }
+    } else {
+      const stackTraceForEvent = Trace.Extras.StackTraceForEvent.get(event, parsedTrace);
+      if (stackTraceForEvent) {
+        contentHelper.addSection(i18nString(UIStrings.stackTrace));
+        contentHelper.createChildStackTraceElement(stackTraceForEvent);
+        // TODO(andoli): also build stack trace component for other events
+        // that have a stack trace using the StackTraceForEvent helper.
+      } else {
+        const stackTrace = Trace.Helpers.Trace.getZeroIndexedStackTraceForEvent(event);
+        if (stackTrace?.length) {
+          contentHelper.addSection(stackLabel);
+          contentHelper.createChildStackTraceElement(TimelineUIUtils.stackTraceFromCallFrames(stackTrace));
+        }
       }
     }
     switch (event.name) {