DevTools: Make timeline show the JS stacks for microtasks.

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

Index: third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp b/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
index ccd7a6f1f3efd7f276404ceecb5153aba848bd6e..6117ad46d8f0acfdf01748eeb04666b91d31ad83 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
@@ -458,11 +458,16 @@ v8::MaybeLocal<v8::Value> V8ScriptRunner::callFunction(v8::Local<v8::Function> f
     }
     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;