DevTools: Make timeline show the JS stacks for microtasks.

third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 440 matching lines @@
         return v8::MaybeLocal<v8::Value>(throwStackOverflowExceptionIfNeeded(isolate));
 
     RELEASE_ASSERT(!context->isIteratingOverObservers());
 
     if (ScriptForbiddenScope::isScriptForbidden()) {
         throwScriptForbiddenException(isolate);
         return v8::MaybeLocal<v8::Value>();
     }
     if (!depth)
         TRACE_EVENT_BEGIN1("devtools.timeline", "FunctionCall", "data", InspectorFunctionCallEvent::data(context, function));
-    v8::MicrotasksScope microtasksScope(isolate, v8::MicrotasksScope::kRunMicrotasks);
-    ThreadDebugger::willExecuteScript(isolate, function->ScriptId());
-    v8::MaybeLocal<v8::Value> result = function->Call(isolate->GetCurrentContext(), receiver, argc, args);
-    crashIfIsolateIsDead(isolate);
-    ThreadDebugger::didExecuteScript(isolate);
+    v8::MaybeLocal<v8::Value> result;
+    {
+        // Create an extra block so FunctionCall trace event end phase is recorded after
+        // v8::MicrotasksScope destructor, as the latter is running microtasks.
+        v8::MicrotasksScope microtasksScope(isolate, v8::MicrotasksScope::kRunMicrotasks);
+        ThreadDebugger::willExecuteScript(isolate, function->ScriptId());
+        result = function->Call(isolate->GetCurrentContext(), receiver, argc, args);
+        crashIfIsolateIsDead(isolate);
+        ThreadDebugger::didExecuteScript(isolate);
+    }
     if (!depth)
         TRACE_EVENT_END0("devtools.timeline", "FunctionCall");
     return result;
 }
 
 v8::MaybeLocal<v8::Value> V8ScriptRunner::callInternalFunction(v8::Local<v8::Function> function, v8::Local<v8::Value> receiver, int argc, v8::Local<v8::Value> args[], v8::Isolate* isolate)
 {
     TRACE_EVENT0("v8", "v8.callFunction");
     TRACE_EVENT_SCOPED_SAMPLING_STATE("v8", "V8Execution");
     v8::MicrotasksScope microtasksScope(isolate, v8::MicrotasksScope::kDoNotRunMicrotasks);
@@ skipping 51 matching lines @@
 // Store a timestamp to the cache as hint.
 void V8ScriptRunner::setCacheTimeStamp(CachedMetadataHandler* cacheHandler)
 {
     double now = WTF::currentTime();
     unsigned tag = cacheTag(CacheTagTimeStamp, cacheHandler);
     cacheHandler->clearCachedMetadata(CachedMetadataHandler::CacheLocally);
     cacheHandler->setCachedMetadata(tag, reinterpret_cast<char*>(&now), sizeof(now), CachedMetadataHandler::SendToPlatform);
 }
 
 } // namespace blink