Set profiler values to doubles

Author: sebmarkbage

packages/react-reconciler/src/ReactFiber.js

@@ -187,18 +187,11 @@ function FiberNode(
     // Learn more about this here:
     // https://github.com/facebook/react/issues/14365
     // https://bugs.chromium.org/p/v8/issues/detail?id=8538
-    this.actualDuration = Number.NaN;
-    this.actualStartTime = Number.NaN;
-    this.selfBaseDuration = Number.NaN;
-    this.treeBaseDuration = Number.NaN;
-
-    // It's okay to replace the initial doubles with smis after initialization.
-    // This won't trigger the performance cliff mentioned above,
-    // and it simplifies other profiler code (including DevTools).
-    this.actualDuration = 0;
-    this.actualStartTime = -1;
-    this.selfBaseDuration = 0;
-    this.treeBaseDuration = 0;
+
+    this.actualDuration = -0;
+    this.actualStartTime = -1.1;
+    this.selfBaseDuration = -0;
+    this.treeBaseDuration = -0;
   }
 
   if (__DEV__) {
@@ -286,10 +279,10 @@ function createFiberImplObject(
   };
 
   if (enableProfilerTimer) {
-    fiber.actualDuration = 0;
-    fiber.actualStartTime = -1;
-    fiber.selfBaseDuration = 0;
-    fiber.treeBaseDuration = 0;
+    fiber.actualDuration = -0;
+    fiber.actualStartTime = -1.1;
+    fiber.selfBaseDuration = -0;
+    fiber.treeBaseDuration = -0;
   }
 
   if (__DEV__) {
@@ -382,8 +375,8 @@ export function createWorkInProgress(current: Fiber, pendingProps: any): Fiber {
       // This prevents time from endlessly accumulating in new commits.
       // This has the downside of resetting values for different priority renders,
       // But works for yielding (the common case) and should support resuming.
-      workInProgress.actualDuration = 0;
-      workInProgress.actualStartTime = -1;
+      workInProgress.actualDuration = -0;
+      workInProgress.actualStartTime = -1.1;
     }
   }
 

packages/react-reconciler/src/ReactFiberBeginWork.js

@@ -2430,10 +2430,10 @@ function mountSuspenseFallbackChildren(
       // final amounts. This seems counterintuitive, since we're intentionally
       // not measuring part of the render phase, but this makes it match what we
       // do in Concurrent Mode.
-      primaryChildFragment.actualDuration = 0;
-      primaryChildFragment.actualStartTime = -1;
-      primaryChildFragment.selfBaseDuration = 0;
-      primaryChildFragment.treeBaseDuration = 0;
+      primaryChildFragment.actualDuration = -0;
+      primaryChildFragment.actualStartTime = -1.1;
+      primaryChildFragment.selfBaseDuration = -0;
+      primaryChildFragment.treeBaseDuration = -0;
     }
 
     fallbackChildFragment = createFiberFromFragment(
@@ -2560,8 +2560,8 @@ function updateSuspenseFallbackChildren(
       // final amounts. This seems counterintuitive, since we're intentionally
       // not measuring part of the render phase, but this makes it match what we
       // do in Concurrent Mode.
-      primaryChildFragment.actualDuration = 0;
-      primaryChildFragment.actualStartTime = -1;
+      primaryChildFragment.actualDuration = -0;
+      primaryChildFragment.actualStartTime = -1.1;
       primaryChildFragment.selfBaseDuration =
         currentPrimaryChildFragment.selfBaseDuration;
       primaryChildFragment.treeBaseDuration =