Fix wrong VSYNC event (#36775)

Author: fzyzcjy

shell/common/vsync_waiter.cc

@@ -89,6 +89,17 @@ void VsyncWaiter::FireCallback(fml::TimePoint frame_start_time,
                                bool pause_secondary_tasks) {
   FML_DCHECK(fml::TimePoint::Now() >= frame_start_time);
 
+  // The event named "VSYNC" is special in `chrome://tracing` tool - it will
+  // have a zebra visualization.
+  fml::tracing::TraceTimelineEvent(
+      "flutter", "VSYNC", frame_start_time.ToEpochDelta().ToMicroseconds(), 0,
+      Dart_Timeline_Event_Begin, {"frame_start_time", "frame_target_time"},
+      {std::to_string(frame_start_time.ToEpochDelta().ToMicroseconds()),
+       std::to_string(frame_target_time.ToEpochDelta().ToMicroseconds())});
+  fml::tracing::TraceTimelineEvent(
+      "flutter", "VSYNC", frame_target_time.ToEpochDelta().ToMicroseconds(), 0,
+      Dart_Timeline_Event_End, {}, {});
+
   Callback callback;
   std::vector<fml::closure> secondary_callbacks;
 

shell/common/vsync_waiter_fallback.cc

@@ -35,7 +35,7 @@ VsyncWaiterFallback::~VsyncWaiterFallback() = default;
 
 // |VsyncWaiter|
 void VsyncWaiterFallback::AwaitVSync() {
-  TRACE_EVENT0("flutter", "VSYNC");
+  TRACE_EVENT0("flutter", "VsyncCallback");
 
   constexpr fml::TimeDelta kSingleFrameInterval =
       fml::TimeDelta::FromSecondsF(1.0 / 60.0);

shell/platform/android/vsync_waiter_android.cc

@@ -52,7 +52,7 @@ void VsyncWaiterAndroid::AwaitVSync() {
 
 // static
 void VsyncWaiterAndroid::OnVsyncFromNDK(int64_t frame_nanos, void* data) {
-  TRACE_EVENT0("flutter", "VSYNC");
+  TRACE_EVENT0("flutter", "VsyncCallback");
 
   auto frame_time = fml::TimePoint::FromEpochDelta(
       fml::TimeDelta::FromNanoseconds(frame_nanos));
@@ -72,7 +72,7 @@ void VsyncWaiterAndroid::OnVsyncFromJava(JNIEnv* env,
                                          jlong frameDelayNanos,
                                          jlong refreshPeriodNanos,
                                          jlong java_baton) {
-  TRACE_EVENT0("flutter", "VSYNC");
+  TRACE_EVENT0("flutter", "VsyncCallback");
 
   auto frame_time =
       fml::TimePoint::Now() - fml::TimeDelta::FromNanoseconds(frameDelayNanos);

shell/platform/darwin/ios/framework/Source/vsync_waiter_ios.mm

@@ -102,7 +102,7 @@ - (void)pause {
 }
 
 - (void)onDisplayLink:(CADisplayLink*)link {
-  TRACE_EVENT0("flutter", "VSYNC");
+  TRACE_EVENT0("flutter", "VsyncCallback");
 
   CFTimeInterval delay = CACurrentMediaTime() - link.timestamp;
   fml::TimePoint frame_start_time = fml::TimePoint::Now() - fml::TimeDelta::FromSecondsF(delay);