Add flow events connecting pointer events to frames (#7807)

shell/common/animator.cc

@@ -62,6 +62,17 @@ void Animator::SetDimensionChangePending() {
   dimension_change_pending_ = true;
 }
 
+void Animator::EnqueueTraceFlowId(uint64_t trace_flow_id) {
+  fml::TaskRunner::RunNowOrPostTask(
+      task_runners_.GetUITaskRunner(),
+      [self = weak_factory_.GetWeakPtr(), trace_flow_id] {
+        if (!self) {
+          return;
+        }
+        self->trace_flow_ids_.push_back(trace_flow_id);
+      });
+}
+
 // This Parity is used by the timeline component to correctly align
 // GPU Workloads events with their respective Framework Workload.
 const char* Animator::FrameParity() {
@@ -78,6 +89,13 @@ void Animator::BeginFrame(fml::TimePoint frame_start_time,
                           fml::TimePoint frame_target_time) {
   TRACE_EVENT_ASYNC_END0("flutter", "Frame Request Pending", frame_number_++);
 
+  TRACE_EVENT0("flutter", "Animator::BeginFrame");
+  while (!trace_flow_ids_.empty()) {
+    uint64_t trace_flow_id = trace_flow_ids_.front();
+    TRACE_FLOW_END("flutter", "DispatchPointerDataPacket", trace_flow_id);
+    trace_flow_ids_.pop_front();
+  }
+
   frame_scheduled_ = false;
   notify_idle_task_id_++;
   regenerate_layer_tree_ = false;

shell/common/animator.h

@@ -5,6 +5,8 @@
 #ifndef FLUTTER_SHELL_COMMON_ANIMATOR_H_
 #define FLUTTER_SHELL_COMMON_ANIMATOR_H_
 
+#include <deque>
+
 #include "flutter/common/task_runners.h"
 #include "flutter/fml/memory/ref_ptr.h"
 #include "flutter/fml/memory/weak_ptr.h"
@@ -48,6 +50,10 @@ class Animator final {
 
   void SetDimensionChangePending();
 
+  // Enqueue |trace_flow_id| into |trace_flow_ids_|.  The corresponding flow
+  // will be ended during the next |BeginFrame|.
+  void EnqueueTraceFlowId(uint64_t trace_flow_id);
+
  private:
   using LayerTreePipeline = flutter::Pipeline<flow::LayerTree>;
 
@@ -77,6 +83,7 @@ class Animator final {
   int notify_idle_task_id_;
   bool dimension_change_pending_;
   SkISize last_layer_tree_size_;
+  std::deque<uint64_t> trace_flow_ids_;
 
   fml::WeakPtrFactory<Animator> weak_factory_;
 

shell/common/engine.cc

@@ -355,7 +355,11 @@ void Engine::HandleSettingsPlatformMessage(blink::PlatformMessage* message) {
   }
 }
 
-void Engine::DispatchPointerDataPacket(const blink::PointerDataPacket& packet) {
+void Engine::DispatchPointerDataPacket(const blink::PointerDataPacket& packet,
+                                       uint64_t trace_flow_id) {
+  TRACE_EVENT0("flutter", "Engine::DispatchPointerDataPacket");
+  TRACE_FLOW_STEP("flutter", "PointerEvent", trace_flow_id);
+  animator_->EnqueueTraceFlowId(trace_flow_id);
   runtime_controller_->DispatchPointerDataPacket(packet);
 }
 

shell/common/engine.h

@@ -104,7 +104,8 @@ class Engine final : public blink::RuntimeDelegate {
 
   void DispatchPlatformMessage(fml::RefPtr<blink::PlatformMessage> message);
 
-  void DispatchPointerDataPacket(const blink::PointerDataPacket& packet);
+  void DispatchPointerDataPacket(const blink::PointerDataPacket& packet,
+                                 uint64_t trace_flow_id);
 
   void DispatchSemanticsAction(int id,
                                blink::SemanticsAction action,

shell/common/shell.cc

@@ -546,14 +546,18 @@ void Shell::OnPlatformViewDispatchPlatformMessage(
 // |shell::PlatformView::Delegate|
 void Shell::OnPlatformViewDispatchPointerDataPacket(
     std::unique_ptr<blink::PointerDataPacket> packet) {
+  TRACE_EVENT0("flutter", "Shell::OnPlatformViewDispatchPointerDataPacket");
+  TRACE_FLOW_BEGIN("flutter", "PointerEvent", next_pointer_flow_id_);
   FML_DCHECK(is_setup_);
   FML_DCHECK(task_runners_.GetPlatformTaskRunner()->RunsTasksOnCurrentThread());
   task_runners_.GetUITaskRunner()->PostTask(fml::MakeCopyable(
-      [engine = engine_->GetWeakPtr(), packet = std::move(packet)] {
+      [engine = engine_->GetWeakPtr(), packet = std::move(packet),
+       flow_id = next_pointer_flow_id_] {
         if (engine) {
-          engine->DispatchPointerDataPacket(*packet);
+          engine->DispatchPointerDataPacket(*packet, flow_id);
         }
       }));
+  next_pointer_flow_id_++;
 }
 
 // |shell::PlatformView::Delegate|

shell/common/shell.h

@@ -99,6 +99,8 @@ class Shell final : public PlatformView::Delegate,
       service_protocol_handlers_;
   bool is_setup_ = false;
 
+  uint64_t next_pointer_flow_id_ = 0;
+
   Shell(blink::TaskRunners task_runners, blink::Settings settings);
 
   static std::unique_ptr<Shell> CreateShellOnPlatformThread(

shell/platform/android/android_shell_holder.cc

@@ -192,12 +192,18 @@ void AndroidShellHolder::DispatchPointerDataPacket(
     return;
   }
 
+  TRACE_EVENT0("flutter", "AndroidShellHolder::DispatchPointerDataPacket");
+  TRACE_FLOW_BEGIN("flutter", "PointerEvent", next_pointer_flow_id_);
+
   shell_->GetTaskRunners().GetUITaskRunner()->PostTask(fml::MakeCopyable(
-      [engine = shell_->GetEngine(), packet = std::move(packet)] {
+      [engine = shell_->GetEngine(), packet = std::move(packet),
+       flow_id = next_pointer_flow_id_] {
         if (engine) {
-          engine->DispatchPointerDataPacket(*packet);
+          engine->DispatchPointerDataPacket(*packet, flow_id);
         }
       }));
+
+  next_pointer_flow_id_++;
 }
 
 Rasterizer::Screenshot AndroidShellHolder::Screenshot(

shell/platform/android/android_shell_holder.h

@@ -52,6 +52,7 @@ class AndroidShellHolder {
   std::unique_ptr<Shell> shell_;
   bool is_valid_ = false;
   pthread_key_t thread_destruct_key_;
+  uint64_t next_pointer_flow_id_;
 
   static void ThreadDestructCallback(void* value);
 

shell/platform/embedder/embedder_engine.cc

@@ -89,12 +89,17 @@ bool EmbedderEngine::DispatchPointerDataPacket(
     return false;
   }
 
+  TRACE_EVENT0("flutter", "EmbedderEngine::DispatchPointerDataPacket");
+  TRACE_FLOW_BEGIN("flutter", "PointerEvent", next_pointer_flow_id_);
+
   shell_->GetTaskRunners().GetUITaskRunner()->PostTask(fml::MakeCopyable(
-      [engine = shell_->GetEngine(), packet = std::move(packet)] {
+      [engine = shell_->GetEngine(), packet = std::move(packet),
+       flow_id = next_pointer_flow_id_] {
         if (engine) {
-          engine->DispatchPointerDataPacket(*packet);
+          engine->DispatchPointerDataPacket(*packet, flow_id);
         }
       }));
+  next_pointer_flow_id_++;
 
   return true;
 }

shell/platform/embedder/embedder_engine.h

@@ -56,6 +56,7 @@ class EmbedderEngine {
   const EmbedderExternalTextureGL::ExternalTextureCallback
       external_texture_callback_;
   bool is_valid_ = false;
+  uint64_t next_pointer_flow_id_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(EmbedderEngine);
 };