Log the time from the previous commit to the next render start as animating

If we start a new render on the same track before the previous one finishes
we'll start logging new renders on that track but we should first log the
time between the two renders as animating.

Author: sebmarkbage

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -1957,6 +1957,7 @@ function prepareFreshStack(root: FiberRoot, lanes: Lanes): Fiber {
       }
       finalizeRender(workInProgressRootRenderLanes, renderStartTime);
     }
+    const previousUpdateTask = workInProgressUpdateTask;
 
     workInProgressUpdateTask = null;
     if (includesSyncLane(lanes) || includesBlockingLane(lanes)) {
@@ -1969,18 +1970,30 @@ function prepareFreshStack(root: FiberRoot, lanes: Lanes): Fiber {
         blockingEventTime >= 0 && blockingEventTime < blockingClampTime
           ? blockingClampTime
           : blockingEventTime;
+      const clampedRenderStartTime = // Clamp the suspended time to the first event/update.
+        clampedEventTime >= 0
+          ? clampedEventTime
+          : clampedUpdateTime >= 0
+            ? clampedUpdateTime
+            : renderStartTime;
       if (blockingSuspendedTime >= 0) {
-        setCurrentTrackFromLanes(lanes);
+        setCurrentTrackFromLanes(SyncLane);
         logSuspendedWithDelayPhase(
           blockingSuspendedTime,
-          // Clamp the suspended time to the first event/update.
-          clampedEventTime >= 0
-            ? clampedEventTime
-            : clampedUpdateTime >= 0
-              ? clampedUpdateTime
-              : renderStartTime,
+          clampedRenderStartTime,
           lanes,
-          workInProgressUpdateTask,
+          previousUpdateTask,
+        );
+      } else if (
+        includesSyncLane(animatingLanes) ||
+        includesBlockingLane(animatingLanes)
+      ) {
+        // If this lane is still animating, log the time from previous render finishing to now as animating.
+        setCurrentTrackFromLanes(SyncLane);
+        logAnimatingPhase(
+          blockingClampTime,
+          clampedRenderStartTime,
+          previousUpdateTask,
         );
       }
       logBlockingStart(
@@ -2012,19 +2025,29 @@ function prepareFreshStack(root: FiberRoot, lanes: Lanes): Fiber {
         transitionEventTime >= 0 && transitionEventTime < transitionClampTime
           ? transitionClampTime
           : transitionEventTime;
+      const clampedRenderStartTime =
+        // Clamp the suspended time to the first event/update.
+        clampedEventTime >= 0
+          ? clampedEventTime
+          : clampedUpdateTime >= 0
+            ? clampedUpdateTime
+            : renderStartTime;
       if (transitionSuspendedTime >= 0) {
-        setCurrentTrackFromLanes(lanes);
+        setCurrentTrackFromLanes(SomeTransitionLane);
         logSuspendedWithDelayPhase(
           transitionSuspendedTime,
-          // Clamp the suspended time to the first event/update.
-          clampedEventTime >= 0
-            ? clampedEventTime
-            : clampedUpdateTime >= 0
-              ? clampedUpdateTime
-              : renderStartTime,
+          clampedRenderStartTime,
           lanes,
           workInProgressUpdateTask,
         );
+      } else if (includesTransitionLane(animatingLanes)) {
+        // If this lane is still animating, log the time from previous render finishing to now as animating.
+        setCurrentTrackFromLanes(SomeTransitionLane);
+        logAnimatingPhase(
+          transitionClampTime,
+          clampedRenderStartTime,
+          previousUpdateTask,
+        );
       }
       logTransitionStart(
         clampedStartTime,
@@ -2040,6 +2063,20 @@ function prepareFreshStack(root: FiberRoot, lanes: Lanes): Fiber {
       );
       clearTransitionTimers();
     }
+    if (includesRetryLane(lanes)) {
+      if (includesRetryLane(animatingLanes)) {
+        // If this lane is still animating, log the time from previous render finishing to now as animating.
+        setCurrentTrackFromLanes(SomeRetryLane);
+        logAnimatingPhase(retryClampTime, renderStartTime, previousUpdateTask);
+      }
+    }
+    if (includesIdleGroupLanes(lanes)) {
+      if (includesIdleGroupLanes(animatingLanes)) {
+        // If this lane is still animating, log the time from previous render finishing to now as animating.
+        setCurrentTrackFromLanes(IdleLane);
+        logAnimatingPhase(idleClampTime, renderStartTime, previousUpdateTask);
+      }
+    }
   }
 
   const timeoutHandle = root.timeoutHandle;