From f4f334e5cfb15e1d8abaf2dd6d3b440f96e521ce Mon Sep 17 00:00:00 2001
From: garyqian <garyq@google.com>
Date: Thu, 14 Feb 2019 11:22:57 -0800
Subject: [PATCH] Track flow id

---
 .../darwin/ios/framework/Source/FlutterEngine.mm     | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm b/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm
index 6a855650b9125..8b8bd33fdba2a 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm
@@ -10,6 +10,7 @@
 
 #include "flutter/fml/message_loop.h"
 #include "flutter/fml/platform/darwin/platform_version.h"
+#include "flutter/fml/trace_event.h"
 #include "flutter/shell/common/engine.h"
 #include "flutter/shell/common/platform_view.h"
 #include "flutter/shell/common/shell.h"
@@ -61,6 +62,8 @@ @implementation FlutterEngine {
 
   int64_t _nextTextureId;
 
+  uint64_t _nextPointerFlowId;
+
   BOOL _allowHeadlessExecution;
 }
 
@@ -117,12 +120,15 @@ - (void)updateViewportMetrics:(blink::ViewportMetrics)viewportMetrics {
 }
 
 - (void)dispatchPointerDataPacket:(std::unique_ptr<blink::PointerDataPacket>)packet {
-  self.shell.GetTaskRunners().GetUITaskRunner()->PostTask(
-      fml::MakeCopyable([engine = self.shell.GetEngine(), packet = std::move(packet)] {
+  TRACE_EVENT0("flutter", "dispatchPointerDataPacket");
+  TRACE_FLOW_BEGIN("flutter", "PointerEvent", _nextPointerFlowId);
+  self.shell.GetTaskRunners().GetUITaskRunner()->PostTask(fml::MakeCopyable(
+      [engine = self.shell.GetEngine(), packet = std::move(packet), flow_id = _nextPointerFlowId] {
         if (engine) {
-          engine->DispatchPointerDataPacket(*packet);
+          engine->DispatchPointerDataPacket(*packet, flow_id);
         }
       }));
+  _nextPointerFlowId++;
 }
 
 - (fml::WeakPtr<shell::PlatformView>)platformView {