Only use/define getFiberName where we actually need it

It might be better still to use a getFiberName where appropriate
but this makes the PR less intrusive. We can cherry-pick the
commit that introduced getFiberName as a whole later if need be.

Author: eps1lon

packages/react-reconciler/src/ReactDebugFiberPerf.js

@@ -35,14 +35,6 @@ type MeasurementPhase =
   | 'getChildContext'
   | 'getSnapshotBeforeUpdate';
 
-const getFiberName = (fiber: Fiber): string | null => {
-  if (fiber.tag === SimpleMemoComponent) {
-    return getComponentName(fiber.elementType);
-  }
-
-  return getComponentName(fiber.type);
-};
-
 // Prefix measurements so that it's possible to filter them.
 // Longer prefixes are hard to read in DevTools.
 const reactEmoji = '\u269B';
@@ -127,6 +119,15 @@ const getFiberLabel = (
   }
 };
 
+const getFiberName = (fiber: Fiber): string | null => {
+  if (fiber.tag === SimpleMemoComponent) {
+    const innerName = getComponentName(fiber.type);
+    return `Memo${innerName !== null ? `(${innerName})` : ''}`;
+  }
+
+  return getComponentName(fiber.type);
+};
+
 const beginFiberMark = (
   fiber: Fiber,
   phase: MeasurementPhase | null,