Fabric: Collecting mounting time inside MountingTelemetry

Summary:
Now we also collect mounting time inside MountingTelemetry.
We will use it soon.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: mdvacca

Differential Revision: D18285826

fbshipit-source-id: 512fc62c210a111614b0defb0d76cbd6228fe89f

React/Fabric/Mounting/RCTMountingManager.mm

@@ -269,12 +269,15 @@ static void RNPerformMountInstructions(
   }
 
   RCTAssertMainQueue();
-  auto metadata = MountingTransactionMetadata{surfaceId, transaction->getNumber(), transaction->getTelemetry()};
+  auto telemetry = transaction->getTelemetry();
+  auto number = transaction->getNumber();
 
   [self.delegate mountingManager:self willMountComponentsWithRootTag:surfaceId];
-  _observerCoordinator.notifyObserversMountingTransactionWillMount(metadata);
+  _observerCoordinator.notifyObserversMountingTransactionWillMount({surfaceId, number, telemetry});
+  telemetry.willMount();
   RNPerformMountInstructions(mutations, self.componentViewRegistry, _observerCoordinator, surfaceId);
-  _observerCoordinator.notifyObserversMountingTransactionDidMount(metadata);
+  telemetry.didMount();
+  _observerCoordinator.notifyObserversMountingTransactionDidMount({surfaceId, number, telemetry});
   [self.delegate mountingManager:self didMountComponentsWithRootTag:surfaceId];
 }
 

ReactCommon/fabric/mounting/MountingTelemetry.cpp

@@ -51,6 +51,18 @@ void MountingTelemetry::didLayout() {
   layoutEndTime_ = monotonicTimeInMilliseconds();
 }
 
+void MountingTelemetry::willMount() {
+  assert(mountStartTime_ == kUndefinedTime);
+  assert(mountEndTime_ == kUndefinedTime);
+  mountStartTime_ = monotonicTimeInMilliseconds();
+}
+
+void MountingTelemetry::didMount() {
+  assert(mountStartTime_ != kUndefinedTime);
+  assert(mountEndTime_ == kUndefinedTime);
+  mountEndTime_ = monotonicTimeInMilliseconds();
+}
+
 int64_t MountingTelemetry::getDiffStartTime() const {
   assert(diffStartTime_ != kUndefinedTime);
   assert(diffEndTime_ != kUndefinedTime);
@@ -91,5 +103,17 @@ int64_t MountingTelemetry::getLayoutEndTime() const {
   return layoutEndTime_;
 }
 
+int64_t MountingTelemetry::getMountStartTime() const {
+  assert(mountStartTime_ != kUndefinedTime);
+  assert(mountEndTime_ != kUndefinedTime);
+  return mountStartTime_;
+}
+
+int64_t MountingTelemetry::getMountEndTime() const {
+  assert(mountStartTime_ != kUndefinedTime);
+  assert(mountEndTime_ != kUndefinedTime);
+  return mountEndTime_;
+}
+
 } // namespace react
 } // namespace facebook

ReactCommon/fabric/mounting/MountingTelemetry.h

@@ -28,6 +28,8 @@ class MountingTelemetry final {
   void didCommit();
   void willLayout();
   void didLayout();
+  void willMount();
+  void didMount();
 
   /*
    * Reading
@@ -39,6 +41,8 @@ class MountingTelemetry final {
   int64_t getCommitStartTime() const;
   int64_t getCommitEndTime() const;
   int64_t getCommitNumber() const;
+  int64_t getMountStartTime() const;
+  int64_t getMountEndTime() const;
 
  private:
   constexpr static int64_t kUndefinedTime = std::numeric_limits<int64_t>::max();
@@ -50,6 +54,8 @@ class MountingTelemetry final {
   int64_t commitEndTime_{kUndefinedTime};
   int64_t layoutStartTime_{kUndefinedTime};
   int64_t layoutEndTime_{kUndefinedTime};
+  int64_t mountStartTime_{kUndefinedTime};
+  int64_t mountEndTime_{kUndefinedTime};
 };
 
 } // namespace react